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CNC Pumpkin Carver
A Baccalaureate thesis submitted to the Department of Mechanical and Materials Engineering
College of Engineering and Applied Science University of Cincinnati
in partial fulfillment of the
requirements for the degree of
Bachelor of Science
in Mechanical Engineering Technology
By
Adam J Frueh
April 2016
Thesis Advisor:
Professor Janet Dong, Ph.D.
CNC Pumpkin Carver Adam J Frueh
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TABLE OF CONTENTS
TABLE OF CONTENTS .......................................................................................................... II
FIGURES AND SURVEYS ................................................................................................... III
TABLES .................................................................................................................................. V
ABSTRACT ............................................................................................................................ VI
INTRODUCTION .................................................................................................................... 7
PUMPKIN CARVING IS BECOMING MORE COMPLEX AND DETAILED ..................................................................... 7
TECHNICAL KNOWLEDGE ................................................................................................. 7
CNC MACHINES ................................................................................................................................................. 7 CAM AND G-CODE ............................................................................................................................................ 8 MACHINE COMPONENTS ..................................................................................................................................... 8 COSTS ................................................................................................................................................................. 9
SAFTETY ............................................................................................................................... 10
HAZARDS ......................................................................................................................................................... 10 SAFE TOOLS AND PUMPKIN CARVING KITS ........................................................................................................ 11
EXISTING PRODUCTS ........................................................................................................ 12
CUSTOMER FEED BACK .................................................................................................... 13
RESEARCH CONCLUSION ................................................................................................. 13
PRODUCT FEATURES & OBJECTIVES ............................................................................ 13
ALPHA DESIGN / CONCEPTS ............................................................................................ 14
DESIGN #1, STATIONARY TOOL AND X AND Y AXIS ROTATING OBJECT. ........................................................... 14 DESIGN #2, X AXIS ROTATING OBJECT AND Y AXIS TOOL (ROCKING) ............................................................... 15 DESIGN #3, X AXIS ROTATING OBJECT AND Y AXIS TOOL (LEAD SCREW) ........................................................ 15
BETA DESIGN/PART SELECTION .................................................................................... 16
MAIN ASSEMBLY COMPONENTS ........................................................................................................................ 16 Z-AXIS - CARRIAGE .......................................................................................................................................... 17 Y-AXIS – CURVED RAIL AND LIFT .................................................................................................................... 18 X-AXIS – PLATFORM AND VICE ....................................................................................................................... 20 LINEAR RAIL ASSEMBLY .................................................................................................................................. 22 CURVED RAIL ASSEMBLY ................................................................................................................................ 23 SPINDLE AND ACCESSORIES ............................................................................................................................. 24 STEPPER MOTORS AND ELECTRONICS .............................................................................................................. 25 CNC PROGRAM, MACH3 .................................................................................................................................. 26
CRITICAL DESIGN COMPONENTS .................................................................................. 28
COMPONENT ONE, BOTTOM VICE...................................................................................................................... 28 COMPONENT TWO, GEAR TRAIN ....................................................................................................................... 28 COMPONENTS THREE AND FOUR, TIMING BELT CENTER DISTANCE ................................................................. 29 COMPONENT FIVE, COMPRESSION SPRINGS ...................................................................................................... 30
CNC Pumpkin Carver Adam J Frueh
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MANUFACTURING ............................................................................................................. 32
STRUCTURE ...................................................................................................................................................... 32 Z-AXIS - CARRIAGE ..................................................................................................................................... 33 Y-AXIS – CURVED RAIL AND LIFT ........................................................................................................... 34 X-AXIS – PLATFORM AND VICE ............................................................................................................... 35
TESTING ................................................................................................................................ 36
CONCLUSION ....................................................................................................................... 37
WORKS CITED ..................................................................................................................... 37
APPENDIX ............................................................................................................................. 38
A. RESEARCH .............................................................................................................................................. 38 B. SURVEY .................................................................................................................................................. 39 C. QFD ........................................................................................................................................................ 40 D. BILL OF MATERIAL/BUDGET OF MATERIALS ........................................................................................... 41 E. SCHEDULE............................................................................................................................................... 42 F. BUDGET .................................................................................................................................................. 43 G. DATE SHEETS .......................................................................................................................................... 44 H. DRAWINGS .............................................................................................................................................. 46 I. FABRICATED PARTS ................................................................................................................................ 50
Figures and Surveys
1 Older traditional pumpkins
2 Intense carving
3 Professional CNC milling
4 DIY CNC milling machine
5 Carving Kit
6 PunkinBot
7 PunkinBot 2.0
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8 Design Concept 1
9 Design Concept 2
10 Design Concept 3
11 Near Final Product
12 Dremel Rendering
13 Compression Housing
14 Compression Housing Connector
15 Z-Axis Moving Assembly
16 Z-Axis Carriage
17 Curved Rail & Carriage
18 Lead Screw connection
19 Y-Axis Assembly and Z-Axis Assembly
20 Platform, Mounting Arms, and Vice
21 Complete X-Axis Platform and Vice
22 BRA and Gear Train
23 The XYZ Axis together, templates highlighted
24 Aluminum Rails
25 Bearing Assembly
26 BRA
27 BRA riding the rail
28 Complete curved Rail
29 Rail individual Sections
30 Slider w/ V groove bearings
31 Slider on Rail
32 Slider on Rail
33 Finished, Z Axis w/ Nose Cone
34 Nose Cone
35 Protruding Milling Bit
36 Milling Bit
37 NEMA 17
38 NEMA 23
39 2.5 amp Driver
40 Breakout Board
41 Electronic Board
42 Main Screen of Mach3
43 Computer setup
44 EasyCAM
45 Finished Wired Board
46 Deflection visualization
47 Deflection Scale
48 Gear Train Sketch
49 Center Distance
50 Spring Mechanism
51 Front view in the works
52 Left Side view in the works
53 Dremel and Clamps
CNC Pumpkin Carver Adam J Frueh
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54 Complete Housing
55 Z-Axis Carriage
56 Brackets
57 Gluing the Rails
58 Final Lead Screw Platform
59 Top Mounting Arm
60 Bottom Mounting Arm
61 Front wall w/Rail
62 Back wall w/Rail
63 BRA in place
64 Complete Assembly
65 Electronic Panel in place
TABLES
1 Lacerations requiring repair (1)
2 Tendon Laceration (1)
3 Bill of materials and costs
4 Schedule
CNC Pumpkin Carver Adam J Frueh
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ABSTRACT
Halloween is a special holiday for a lot of people in America. It’s hosts event for
children and adults alike. Many take to decorating their homes in tombstones, webs, and
lights. But the most widely accepted tradition is pumpkin carving. Millions of pumpkins will
be grown and sold to families with the intention of carving faces or characters on them.
Designs from the simple to the artistic will made and then be displayed for the holidayed.
However hundreds of accidents happen while carving. This is due to improper use of tools
from the kitchen which are not design to carve up the hard uneven flesh of a pumpkin.
Carvers end up slipping causing severe injuries to their hands and fingers that can lead loss of
function temporarily or permanently in the worst of cases. Some products that have been
released are special carving tools slimier to a saw and dale edge tools. While these do remove
a lot of risk they are not entirely safe. In order to reduce the number of accidents, my senior
project is to design and build an Automated Pumpkin carver and remove the human eliminate
entirely. The end result will be a three axis CNC machine that will be able to milling out a
predetermined design. Allowing the user to make high quality designs at no risk and in a
fraction of the time.
No existing patents, although one similar product. PunkinBot is a father-son project
attempting the same thing. They currently have a machine available upon order and has been
able to live up to the description. However I wish to take the idea forward and design a self-
contained unit to prevent any injury as I would design this as a kiosk type machine to be run
in a store for customer use.
This project can be broken down in to a few key factors. The design will need to
support a wide range of pumpkins that would be specific to carving. The spindle will be
mounted and rotated normal to the pumpkin via a curved rail. The z-axis will need to respond
to an uneven surface that a pumpkin would have.
CNC Pumpkin Carver Adam J Frueh
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Introduction
Halloween is celebrated every year in numerous countries around the world. The holiday
and similar ones like it, are times in the year dedicated to honoring the dead, including saints
or hallows, martyrs, and other member of the respective faith. The tradition is using themes
of humor and ridicule to confront the idea of death. So what do we do for Halloween? Some
people will dress up in costumes (scary or not) and have fun with trick-or-treating. Others
will fixup their house with lights and decorations in the form of webs, tombstones, and other
scary things. But the most popular decoration is Jack-o-Lanterns. A Jack-o-Lantern is a
hollowed-out pumpkin in which holes are cut to represent facial features. This has become a
family tradition for a lot of Americans and others that celebrate Halloween. As digital
imaging technology has improved and simple-to-use media sharing websites have appeared,
the complexity of Halloween jack-o-lanterns being created has been increasing. (2) The past-
time is now deeply rooted into our culture but we have also found it to be a hazardous one.
Improper technic, tools, and supervision for children leads to many cases of hand injuries
reported throughout the holiday. (3)
PUMPKIN CARVING IS BECOMING MORE COMPLEX AND DETAILED
Figure 1 & 2 (4)
Technical Knowledge
CNC MACHINES
If you come from a technical or manufacturing background, then you most likely are
familiar with what a CNC machine is. If not, you should know CNC is an abbreviation for
computer numerical control. A CNC machine, then, is a machine that carves out objects in
CNC Pumpkin Carver Adam J Frueh
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three dimensions from a solid block of material. CNC machines are commonly used in
industry to produce small parts such as bicycle stems and tools. Low-cost CNC machines are
increasingly used by serious hobbyists, especially woodworkers, to carve creations out of
materials such as wood and aluminum (5). Because it’s become so popular, there’s plenty of
different sources referencing “do-it-yourself” CNC machine builds. Although there is a
fundamental difference between a typical CNC and my pumpkin carving CNC Machine.
We can divide the most basic CNC machines into two categories: turning machines and
milling machines. Turning machines works by spinning a work piece at high speed and a tool
(sharp edge) is brought to the surface which begins to shave off the undesired material from
the work piece, the tool will move forward and
back to the center, or up and down the length of
the work piece until the desired shape is
achieved. Milling machines work much
differently, where the machine that has a
spindle or drill that can cut in various directions
and moves in a standard three axis cartesian
motion (5). Figure 3, Professional CNC milling
http://chopshopcnc.com/services/cnc/
CAM AND G-CODE
These configurations have been around for a long time and wouldn’t need a computer to
create parts. But by adding a computer to the machine controls we can achieve higher level
of quality and repeatability. Today CNC machines produce parts from computer aided design
(CAD) files, which are digital three dimensional parts. To produce the part we just need to
specify to the machine how we what the part to be cut, and that comes from a computer-aided
manufacturing (CAM) file or G-code file, there are also other types but are essentially the
same (5). The CAM file contain all of the steps and operations that the machine will follow
to make the part.
MACHINE COMPONENTS
CNC Pumpkin Carver Adam J Frueh
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The typical CNC Machine will have motors and rails which will give the tool motion.
And because the work on a flat plane the design of this can be fairly simple. The turning
CNC machines use a motor to rotate the part and motors and rails to guide the tool. Of these
devices a few speculative design could involve a combination of motions. Choices of the
motors/actuators, CAM, build materials, and tooling depended on the desired performance of
the machine. Some will design their machine for speed, others for a maximum work envelop.
But these choices are directly related to the intended purpose and material worked.
COSTS
A personal CNC machine can be upwards of $3000 dollars to purchase (5). Which is
partly the reason so many engineers, inventors and hobbyist have turned to do-it-yourself
CNC machines. The material for one can be as low as $390 for a small desktop machine. But
the average DIY CNC machine will cost between $700-$800 (5).
Figure 4, Example of a ‘do it yourself’ CNC milling machine
http://www.wired.com/2011/01/diy-cnc-machine-just-390/
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Saftety
HAZARDS
Traditional pumpkin carving is dangerous if you don’t have the right tools and technic.
A true story of one Kim Sillcox. (3)
The mother of two had the pumpkins lined up in the kitchen
of her Aurora home, ready to carve with her children.
Like most, it is a family tradition to turn the bright orange balls
into jack-o'-lanterns to thrill trick-or-treaters, who were set
to arrive on her doorstep. But her pumpkin carving would have consequences.
"I was rushing and we were carving more pumpkins than usual," she said.
"I used a knife I shouldn't have been using." The hand holding the knife,
which was coated with the slippery innards of another pumpkin, slid down to
the blade and she cut right through the tendon of her index finger.
It happened in a flash.
These lead to Ms. Sillcox having to undergo surgery and was involved in three months
of rehabilitation. “Afterwards it still left her without the ability to use, touch, or
independently wash the injured hand” (3). Her hand surgeon, Dr. Deborah vanVliet and her
therapist Lucy Winston both agree pumpkin carving wounds can be very serious and may
need intensive surgeries and recovery times of up to four months (3).
"Flexor tendons are like elastic bands and are under a tremendous amount of tension
from the muscles in the forearms," Dr. vanVliet said. "One small and simple cut can cause
the tendons to retract like an elastic and the whole hand can lose its ability to move and
bend." (3). Southlake alone will see close to 30 cases of tendon injuries yearly, spiking in
numbers around Thanksgiving and Halloween, when people get caught up in celebrations. (3)
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SAFE TOOLS AND PUMPKIN CARVING KITS
Because it has become fundamentally known that you
should take extra precautions when carving pumpkins,
some companies have made up and released special kits for
carving pumpkins safely. The design off these tools do
make it easy to carve a pumpkin, they do not have a single
long blade but instead fashion a serrated or saw like blade.
Some resemble band saws like the ones meant for sawing
wood. While this does reduce the likely hood of injury, the
tool can still cause still cause injuries. (6) Figure 5 Carving kit (7)
Natalie Greaves, mother in the U.K. was shocked to learn her young son was able to go
to the local grocery store and purchase a pumpkin carving kit, which contained several sharp
serrated knife. “I went berserk when he came home with it. I couldn’t believe that he could
pick that sort of thing up as a child - there should have been an age restriction on it,” said
Greaves. (7)
Studies have been done on a variety of tools and compared also with house old kitchen
knives. “Examination of the fingers after being tested with each knife revealed that more
laceration injuries occurred with either of the kitchen knives than the pumpkin knives” (1)
The four knife types demonstrated that there were statistical differences in the number of
lacerations in the skin, the FDP and the FDS slips between knife types.
CNC Pumpkin Carver Adam J Frueh
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Table 1
Existing Products
Besides Pumpkin carving kits, what about other CNC machines. The idea of carving a
pumpkin with a CNC machine is not new. The first one to do it were most likely shop
technicians and hobbyist simply fixing his pumpkin under a mill and just tried it. You can
find a few videos online giving examples of this. While it has potential to look great and
produce detailed images, it can only approach the pumpkin from one side. Giving the image
an extended cut appearance.
I’ve only found one machine that has tried to tackle this problem as it was designed to
carve pumpkins. The brainchild of a father and son project, the PunkinBoT & PunkinBot 2.0
(8). The quality of their work is impressive, it is accomplishing what I intend to do when my
design but when I look at the machines I see it has a lot in common with Halloween, big and
scary. “…sadly, the PunkinBoT 2.0 has a little less of the Halloween macabre: The original
carried out the carving with what looked an awful lot like a severed arm.” (8) This can be
bought online and is built to order. I believe this would be suited for either a Halloween
hobbyist or interested machinist.
Figure 6, PunkinBoT Figure 7, PunkinBot 2.0
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Customer Feed Back
The project needs more information from potential end users to determine the best
method and design concepts for the CNC machine, surveys were sent out, few were returned.
But currently we are in the Halloween season and there’s jack-o-lanterns everywhere, I can
survey more and have a better idea of what we should take in to consideration. At the
moment I will be making my assumptions based of my research and few survey results.
The design should be able to make continuous revolutions
The design should be CNC capable, with slight demand for manual controls
The design could be suitable for a hobbyist the is into machines or Halloween
The design could be suitable for use is a Walmart or other garden center.
A standing model will be the focus
And the machine does not need to be FDA certifiable
The work area must be easy to clean.
It must have noise generated to a minimum
Research Conclusion
In summary the project will be following basic instructions from do it yourself guides
on CNC machine construction. Including a textbook and potential other future examples. By
simply changing out a few methods of motion and mechanical drive we can archive a process
that will work martial in a spherical work envelope, much like the PunkinBot but made to be
more marketable, safe, and user friendly.
Product Features & Objectives
Based off of all the research and customer feedback, along with my asumtions we have a
good idea of what to expect. Our purpose is to make a CNC Machine available high quality
jack-o-lantern carving. Top priorities are to make it safe and simple, while taking up the
smallest amount of space. The intention is to have this machine run similar to a vending
machine, or coin counting machine. The intended operation is to run a consumers store
bought pumpkin with or without a clerk to assist. Since it will be in open corporate spaces it
really needs to consider safety and reduce it liability. The machine will then have
preprogramed designs or the possibility to upload a design with a thumb drive. To make this
simple a type of free sourced software will be decided and it needs to mesh with the possible
constraints of the CNC. Tolerances need to be made on the sizes and quality of pumpkin.
What qualify as a good pumpkin? In this case its fresh, round, and not compromised. Still I’ll
need to consider the worst case scenarios.
CNC Pumpkin Carver Adam J Frueh
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Objectives
-Achieve a fast cutting speed, Goal of under ten minutes.
-Slim profile and small foot print
-Match power and size of the tooling to desired cutting speed
-Simple design, minimize electric systems and part count
-Sealed work space for safety
-Designed for vending, (Walmart, Garden Center, Pumpkin Farm)
Alpha Design / Concepts
It’s very important to know everything that will go into the product and to have set goals
in mind. There’s a big difference between what I want to do and what my capabilities are.
My thought pattern has changed on how I could build this machine within my budget, time
frame and design complexity. When I talk about these designs, know that the z axis was
always implemented where the tool will be driven in to the medium.
DESIGN #1, STATIONARY TOOL AND X AND Y AXIS ROTATING OBJECT.
This was my first idea, I was trying to make the device as small and possible. I wanted to
remove the necessity of parts rotating around the pumpkin in long arcs. I planned to have the
pumpkin rotate on an axis and the axis assembly would rock for the other axis. I quickly
noticed this would not work because of how difficult it would be to design this. Keeping the
pumpkin stationary and on target while it’s begin machined is a difficult task. Plus the added
factor that a pumpkin is heavy and comes in many sizes, I would be fighting gravity in a
worst ways. Cleaning the machine would have been more difficult. I needed to design
something that had more flexibility over machine size.
CNC Pumpkin Carver Adam J Frueh
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Figure 8, Design Concept 1 (right)
Figure 9, Design Concept 2 (left
DESIGN #2, X AXIS ROTATING OBJECT AND Y AXIS TOOL (ROCKING)
This designed had the object upright on a rotating platform and was also held in place
from an above pressure plate. A Counter balanced tool would rock on the Y axis, while It
might have worked, the main reason this idea faded out was the power transition from the
motor to the Y axis would have been to slow and require a lot of torque. The rocker would
have also gotten in the way of the x axis, I tried to work around this but the machine was far
too big. The loading window would be small as well. I was hoping the machine could be
entertaining to watch, since the customer would be standing by waiting for it to finish and
this concept doesn’t do that for me.
DESIGN #3, X AXIS ROTATING OBJECT AND Y AXIS TOOL (LEAD SCREW)
This was the design I’ll be going for my project. This is because it follow everything
good about concept two but more so towards my goals. It’s simple and easily buildable with
in my time frame. The device will run the tool along a curved track which will be powered
by a lead screw. The machine will be smaller since all of the components are off to one side,
leaving plenty of viewing space. Also it will require less material and smaller motors. Plenty
of open area to work with for other functions that could be implemented. After going with
this I also designed a self-centering vice to position the medium in a range of sizes. This will
be hand cranked for the prototype and locked in with a pin. Later models will motorize this
process.
CNC Pumpkin Carver Adam J Frueh
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Figure 10, Design Concept 3 (left)
Figure 11, Near Final Product (Right)
Designing this unit is heavily dependent on the size of the medium. To do this sketches
on the motion axis plane were made. The original range of sizes was determined from the
typical size of pumpkins sold for carving, this is 8 to 15 inches in diameter.
This means our carver needs to have a z-axis range more then 3.5 inchs plus what ever
distance is required to completely remove a drill bit from a 15 inch diameter pumpkin and
another inch for compression. *Originally the z-axis had a distance of 6inch
Beta Design/Part Selection
After completing the basic design, fabrication capabilities were considered. Before and
during the build some parts were changed to make things simpler. Although some of these
changes did make unintended conflicts, the changes were necessary.
MAIN ASSEMBLY COMPONENTS
The CNC Pumpkin carver can be broken down into three main assemblies. This would
be the Y-Axis lift, the Z-Axis carriage, and the X-axis Vice.
First designed was the Y-Axis Lift but more specifically the Curved Rails. As seen in the
concept design the rail radius is concentric for the pumpkin template. Design at 12 inch
radius. The final rails became hollow with a frame over on side for strength and to allow
mounting to panels.
Next this Y-Axis Assembly needed to be built alongside the Z-Axis Carriage, This is
because the lead screw position and length depended upon final dimension of the Dermel
housing.
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Z-AXIS - CARRIAGE
The Z-Axis Carriage would be need to be designed around the Dremel 200 series body.
For the CAD representation an already built
model was found on the website GrabCAD.com
This provided a close to accurate model to work
from, although after sourcing my own tool found
minor changes that needed to be made in
diameters of surfaces critical to mounting the
tool.
Figure #, Dremel 200 Series by username: Vlad
https://grabcad.com/library/dremel-body
Figure 12, Dremel Rendered
The next step was mounting the Dremel tool in such a way as to provide ridged mounting on
to plane and still allow some linear motion for the spring compression mechanism.
The end product was a series of clipping mounts, fixed together by threaded rods.
Figure 13, Compression Housing Figure 14, Compression housing Connector
Notice the cuts on the rear two claps. These provide connection to the Z-Axis Carridge but
will allow a sliding action.
The connection piece also serves as a
push off point for the compression
mechanism. Two of these piece would be
combined by a sheet two pieces of sheet metal
arcing over top. On top of these pieces would
also lay the rack that will transmit motion to
the assembly. This is attached with small
threaded bolts. Also attached to the connector
piece is the slider rail, It’s attached by strong
forces of friction from a reverse angled flange. Figure 15, Z-Axis Moving Assembly
What you see to the right is everything that moves on the Z-Axis, The compression is
CNC Pumpkin Carver Adam J Frueh
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activated when the drill coming into full
contact with the specimen.
The rest of the Z-Axis Carriage includes
the linear rails the bearing rest on, the
motor that will drive the Z-Axis and the
sides of the carriage that will mount to
the Y-Axis rails.
*Orignial Designs had carved away
access material but in interest of saving
time was excluded.
Figure 16, Z-Axis Carriage
Y-AXIS – CURVED RAIL AND LIFT
From this point the outside walls of the carridge need to be attached to the Y-Axis. We
will do this in theory by first attaching the carridge to the Curved rails that will rotate the Z-
Axis Assembly around the Templete. This is done by
attaching to the sliders designed for these rails.
Now that the carridge has the ability to rotate around
the templete we need to power it. This is done by the
main installing a vertical lead screw somewhere centered
behide the carriage. It should be far enough away to not
impede the carriage motion and but also made as close as
possible to reduce the length of the lead screw. The
further away this lead screw the longer it must be to
interact with the next feature.
Figure 17, Curved Rail & Carriage
We attach to the lead screw with a vertically
linear moving platform with rotation ends. The ends
have a linear bearing in them and will rotate with the
angle of the carriage. The linear bearings will prevent
the platform from rotating and also provide the
connection and lift for the carridge. Mounting blocks
for the rods will be attached to the carridge.
Figure 18, Lead screw connection
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Figure 19, Y Axis Assembly and Z-Axis Assembly
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X-AXIS – PLATFORM AND VICE
This sub-assembly is very different from the Y-Axis and
the Z-Axis as they are not directly connected. They will have
their own template at an opposite plane from the Y-Axis’s
template. The Templates in SolidWorks were center and acted
as one in the complete assembly.
The first things designed are the platform for the
pumpkins. This goes along with the mounting arms and the
attachments that will hold the platforms in place. The
mounting arms need to be long enough to be out of the way of
the biggest pumpkins but strong enough to not deflect under
the weight of the pumpkin or the heavier watermelon. The
platform also acts as the X-axis rotating the pumpkin on the
platform driven by a stepper motor. This stepper motor is best
to be also attached to the lower mounting arm to have a direct
and simple drive train to the platform. Although this will
increase the deflection on the arm.
The platforms will
together work as a vice,
driven by a central gear
that will pull them
together. Compressible
foam will hold the
pumpkin in place. The
central gear is on a gear
train leading towards a
hand crank. The goal of
this train is to easy the
lifting of the weight on the
platform and also move
the crank to the front of
the unit.
Flanking each mounting
arms is a set of BRA and
rails to match. These hold
everything together in the
horizontal directions.
Sandwiched between two
walls.
Figure 20, Platform, mounting
arms and vice
Figure 22, BRA and gear train
Figure 21,
Complete X-Axis
platform and Vice
CNC Pumpkin Carver Adam J Frueh
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Figure 23, The XYZ Axis Together, Templates highlighted
Now that we have the main components of a CNC we need to build the structure around the
device. Seen in the above picture we have attached the curved rails to panels with a cut out
for the carriage. We start to see the chambers of our CNC machine.
The forward left chamber will be our viewer/working section. Here is where the Pumpkin
will be loaded and the vice will close on the fruit by the user.
The left rear chamber simply leaves room for the gears and timing belt, in a final model this
would be closed off.
The right chamber will have the Y & Z Axis. There is plenty of room to store other things in
the future like the electronics board.
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LINEAR RAIL ASSEMBLY
Bearing-Rail assembly, I’ve used the term BRA in
other sections of this report to represent this since it’s used
to a hand full of locations. In the test book BYOCNC (5) in
order to get the best movement along all three axes, my
CNC machine is going to use an inexpensive solution that’s
also extremely smooth and accurate. Here’s how it works.
Lengths of aluminum angled rail. These rail consists of two
1/8"- thick walls that meeting at a 90 degree angle (right
angle). Rail width is measured on the outside wall from the
outside edge to the edge where the two walls meet.
This figure shows a few of the pieces of hardware that you’ll
be purchasing—bearing, bolt, and nut. It also shows the three
items assembled. The bearing is the same type of bearing
you’ll find used in skates, 22mm very low-cost
Attaching the BRA can be done in a few ways, the book
suggests drilling pilot holes and screw the rails done, this
works pretty well depending on the heads used. Thou I’ve
Attached mine using bolts, adhesives, zip ties, friction, and
a combination of these for temporary and permanent
placement.
Figure 24, Alum Rails
Figure 25, bearing
assembly
Figure 26, BRA
Figure 27, BRA riding the rail
CNC Pumpkin Carver Adam J Frueh
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CURVED RAIL ASSEMBLY
This design concept calls for a curved rail to
run the z-axis carriage around the pumpkin. This
enables us to stick to a 3 axis CNC machine. What
is more important is it will keep the drill working
the pumpkin normal to the surface. By that I mean
parallel.
The way to do this is to center the arc of the
rail to where the center of the vice will be. It’s also
important to note that the size of the pumpkin Figure 28, Complete Curved Rail
doesn’t effect this.
Much like the linear rail system these rails
keep the movement of our axis confined. The main
difference is since the rail is curved we need a
better way to fix the movement to the rails. The
solution is instead of simple bearings we will need
to use special v-groove bearings to grip the rail,
ranged properly the bearing can also mesh with a
curved rail seen in figure #.
Figure 29, Rail individual sections
When fabricating this rail it is very important
to make sure the curve is perfect. Making this rail
would be very difficult by hand and very costly if
made in a CNC machine. The solution is to make
a rail in a 3D Printer. The rails you see here are
made in the Universities Rapid Prototyping lab.
They are made out of a plastic filament. To make
thing simple the “Slider” is also made on the
printers and allow attachment of the bearings. It’s
important when making 3D parts that need to fit
tight specs that you add a slight tolerance on your
drawings. These parts then to expand slightly in Figure 30, Slider with v-groove Bearings
the heating process, therefor
add .05” to any critical
measurement. The entire rail
wouldn’t fit in the printer, it
was a simple measure to split
them into thirds and design
pegs to hold them together.
Figure 31 & 32, Slider on rails
CNC Pumpkin Carver Adam J Frueh
24
SPINDLE AND ACCESSORIES
The spindle choice is very important. We need to consider what is necessary for our
needs. Most CNC machines are designed for metal or wood products and require something
powerful but this also means heavy. The heavier the gantry the bigger motors you’ll need and
that means more expensive machinery.
For our needs, carving a fleshy pumpkin, we won’t need anything heavy duty. I’ve chosen to
use the Dremel 200 series because I already owned this tool and would help negate some
costs. The tool is only 2lbs and has a small profile.
Part of this assembly not included in the drawing
is the nose cone. This part extends the physical
connection from the drill to the pumpkin surface that
will compress the springs. The nose can be swapped
out for different lengths. The one shown here will give
us a cutting depth of a quarter inch.
Figure 34, Nose Cone
The milling bit is a special tool. It’s from the RotoZip
sabre cut set. This particular one is meant for drilling
in and milling sideways into wood and plastic sidings.
It will definitely be suited for cutting into pumpkins
and engraving designs.
Figure 35, Protruding milling bit
Figure 33, finished Z-Axis w/nose Figure 36, Milling Bit
CNC Pumpkin Carver Adam J Frueh
25
STEPPER MOTORS AND ELECTRONICS
When picking my stepper motors and the electronics
everything was sourced and suggested by BuildyourCNC.com.
They have very convenient packages and tutorials for the
equipment, not to mention the online forums and quick
customer service has been very helpful.
I decided to go with the NEMA 23 100 Oz-in and the
NEMA 17 62 Oz-in Stepper motors. The X-Axis and the Y-
Axis are going to require some decent torque and the NEMA
100 Oz-in is suggested for my purposes. I decided to do the
NEMA 17 for the Z-Axis for two response, first the reduce Figure 37, NEMA 17
weight and size the second reason is the 100 Oz-in is far more
then what’s necessary.
To drive these motors we will be using the DRV8825
Stepper Motor Controller IC made by Texas Instruments. Each
motor will require its own module to run. This model is a
standalone stepping motor driver that is rated at 2.5 peak amps
per phase. The driver will also accept a range of 8.2 to 45 volts
and can be microstepped up to 1/32 (the step modes are: full,
1/2, 1/4, 1/8, 1/6 and 1/32). The driver chip has all kinds of
built-in protection including protection for heat and over
current. Figure 38, NEMA 23
Connecting the electronics together is the Breakout Board.
I’ve chosen to go with an old fashion parallel port thinking this
would save money thou I didn’t relies my desktop didn’t have a
parallel port. Therefore I went ahead and purchased one for my
computer.
The break out board simply works with the computer Figure 39, 2.5 Amp Driver
program. This board has a relay that controls signals, such
as the router/spindle. There are 11 output pins that can
control various devices such as stepping motor drivers,
coolant, spindle, mist, air, etc. 10 of these pins can be
dedicated to motor axes for a total of 5 axes. 4 Input pins
are provided for limit or home switches.
Lastly to power all of this we purchased a 24 Volt Figure 40, Breakout Board
power supply for the drivers and also a 5 volt adapter for
the breakout board
CNC Pumpkin Carver Adam J Frueh
26
Figure 41, Electronics board
CNC PROGRAM, MACH3
There are three types of software that you’ll be using with your CNC machine. The first
is CAD (computer aided design). This is specialized software that allows you to design two-
and three-dimensional objects for the CNC machine to cut, drill, and perform other actions
on. The second is CAM (computer-aided manufacturing). Easy CAM is the computer-aided
manufacturing). CAM software takes the design you created with the CAD software and
converts it into a “language” called G-Code. This G-
Code is then used by the final type of software,
Control. Control software is the actual application
that talks to your CNC machine; it takes the G-Code
from the CAM software and uses it to send the
proper electrical signals (via the breakout board) to
the three motors.
The Mach3 Control Software is a control
application, It’s from ArtSoft USA and is available
in a free version and a commercial version. Both
versions are identical, but the free version
is going to limit you to 500 lines of G-Code. Figure 42, Main Screen of Mach3
CNC Pumpkin Carver Adam J Frueh
27
When everything is wired on the electronic board, when then connect the computer to
the breakout board using a male-to-male 25-pin cable.
Figure 43, Computer step up Figure 44, Easy CAM
Figure 45, Electronic board
hung up and wired
CNC Pumpkin Carver Adam J Frueh
28
Figure 48, Gear Train
Critical Design Components
By itself, the Pumpkin carver’s parts and components are not heavy enough to cause
failure with the material I’m building with, sheet metal and steel gears. I’ll be using abs
plastic for a few none load bearing parts. This is not designed to hold and drill metal or
wood, just fleshy fruit materials. Pumpkins can weight on average 18 pounds, and I’ll be
designing this for a max load of 30 lbs. Therefore we will need to prevent as much deflection
in our design as possible. Also the hand crank device will need a gear ratio that will allow
ease of use to lift the material.
COMPONENT ONE, BOTTOM VICE
Description: Cantilever
Purpose: Lift and hold material into place
Safety Factor: 2
Load: Static, Moment, 16N at Motor Mount, 130N at the end, 2X factor
of saftey
Figure 46, Deflection visualization
Conclusion: component passes, Max deflection is .01823inchs
and will not be a concern.
COMPONENT TWO, GEAR TRAIN
Description: one timing belt link, one gear link, and two diameter changes
Purpose: Centers both top and bottom platforms
Gear ratio: turn 200N of force into 45N
N1 = 72teeth, 3in Pitch diameter
N2 = 76teeth, 4.72 Pd
N3 = 20teeth, 1.25 Pd
N4 = 48grooves, 3.056 Pd
N5 = 24 grooves, 1.528 Pd
N6 = 3 in Crank wheel
Gear ratio equation: 𝑀𝑣 = (−𝑁2
𝑁3) (−
𝑁4
𝑁5)
𝑀𝑣 = (−76
20) (−
48
24) = 7.6
Figure 47, deflection
scale
CNC Pumpkin Carver Adam J Frueh
29
Central Gear Moment: 200𝑁 × 3𝑖𝑛 = 600𝑁in
After Gear Train: 600𝑁 ×1
7.6= 78.94𝑁
Minimum Crank Moment: 78.94𝑁𝑖𝑛
3𝑖𝑛= 26.31𝑁
Conclustion: Gear Train passes the 45N force required.
COMPONENTS THREE AND FOUR, TIMING BELT CENTER DISTANCE
Description: Two timing belts pulleys positioning
Purpose: Determining bearing mounting positions for no slack blet
Distance Targets: 7in and 9.5in
Originally the supplies website had a center distance calculator to figure out the optimal
distance and belt choice. The actual Distances are Vice platform belt Desired: 9.5 in Actual: 9.587 in X-Axis Belt Desired: 7 Actual: 6.9151in C=Center Distance (in) L=Belt Length (in) = pNB p=Pitch of Belt (in) NB =Number of Teeth on belt = L/p N1=Number of Teeth (grooves) on larger pulley N2=Number of Teeth (grooves) on smaller pulley
=One half angle of wrap on smaller pulley (radians)
=/2 – = angle between straight portion of belt and line of centers (radians)
R1=Pitch Radius of larger pulley (in) = (N1) p/2
R2=Pitch Radius of smaller pulley (in) = (N2) p/2
=3.14159 (ratio of circumference to diameter of circle)
Nomenclature And Basic Equations
2C sin = L – (R1 + R2) – ( – 2) (R1 – R2)
𝐶 = 𝐿 – 𝜋 (𝑅1 + 𝑅2)– (𝜋 – 2𝜙)(𝑅1 – 𝑅2)
2𝑠𝑖𝑛𝜙
Exact Center Distance Determination – Unequal Pulleys The exact equation is as follows: 𝐶 = (1/2)𝜙 [(𝑁𝐵 – 𝑁1) + 𝑘(𝑁1 – 𝑁2)]
where 𝑘 = (– 1) [𝑡𝑎𝑛(– 𝜋 – – 𝜙) + 𝜙 ] is determined from:
1
𝜋(𝑡𝑎𝑛𝜙 − 𝜙) =
(𝑁𝐵 – 𝑁1)
(𝑁1−𝑁2)
CNC Pumpkin Carver Adam J Frueh
30
Figure 49, Center Distance
COMPONENT FIVE, COMPRESSION SPRINGS
Description: Spring mechanism attached to the spindle. Calculate strength
Purpose: Eliminate the need for feedback signals to the controller.
Details: Because a Pumpkin and other possible mediums have a drastically uneven surface
we need a way to keep the z-axis in contact with the surface. The expensive way to do this is
have a feedback signal to the controller with surface distances, typically with CNC machines
this will cause a delay for travel thereby lengthen the process time.
However this could be easily fixed as long as the tool is able to “float” on the surface. A
spring mechanism could achieve this. In theory the tool would fully compress against the
surface triggering a limit switch. Then the z-axis would back of half the compression length.
The result is a tool pressing against the medium. If an uneven surface is more than the
compression distance allow then the limit switch will be activated given a little more room
for moment in that direction
Alpha: Assume frictionless, over engineer
Weight: 5lb
SF:2
10lb ~ 4.53 kg
𝑚𝑔𝑐𝑜𝑠(𝜃) = 𝑁 At 30° 4.53 × 9.81 × 𝑐𝑜𝑠(30) = 38.5𝑁
At 0° 4.53 × 9.81 × 𝑐𝑜𝑠(0) = 44.439𝑁
2 Springs
Choice: Music Wire Precision Compression Spring
Zinc-Plated, 1.5" Length, .48" OD, .063" Wire
Load: 22.94 lb
Conclusion: Two should be enough force
CNC Pumpkin Carver Adam J Frueh
31
Problem: Testing shows the force is far more than necessary to compress.
This error accorded because I converted to Newtons and never converted back.
Solution: Bought several springs to test.
Final Choice: 6lbs/inch rating
Figure 50, Spring mechanism
CNC Pumpkin Carver Adam J Frueh
32
Manufacturing
Fabricating the CNC machine was a huge undertaking, more than I thought it would be.
Several things were changed during the process because they would be too difficult or we
didn’t have the methods available. Regardless, I was able to put together all of the
mechanical components and mechanism. These were made similar to how the design process
went however all at once instead of one element at a time
STRUCTURE
First put together was the outer frame, I did
this because I was going to be aligning everything
and they were going to need a place to be hooked
up to first.
This step was simple, starting with the floor I
installed legs at the same time as mounting the tall
corner beams. The beams are attached to the legs
with several metal corner brackets. This goes the Figure 51, Front view in the works
same for the roof.
For easier caring, I’m attached two sets of
handles to the beams.
Figure 52, Left Side view in the works
CNC Pumpkin Carver Adam J Frueh
33
Z-AXIS - CARRIAGE
The first main component fabricated, like in
the design process is the Z-Axis Carriage.
The clamps are made in the 3D printers and
they are handle together with nuts, spring washers,
and the threaded rods.
Figure 53, Dremel and Clamps
Next was fabricating these sheet metal pieces,
attaching them, the BRAs, and the rack on the top.
This took about 3 days to complete. I’ll be saying this
a lot from now on but the hardest thing about this
projects build is aligning parts and properly drilling
holes. Even then I wasn’t getting smooth spring
action and instead getting binding. After a little
tinkering and grinding of some thread I achieved very
nice linear action.
Figure 54, Complete Housing
The carriage was built alongside the z-axis and
the y-axis. Built as a box, the brackets holding it
together were slightly bent so the box would hold
pressure on the z-axis BRAs. This eliminated some
tolerance issues.
The motor was then mounting and given small
slots so positioning on the rack could be dialed in.
Also attached now is the curved rail sliders seen on
the sides.
Figure 55, Z – Axis Carriage
It was at this point that I recognized some issues.
My designs were very dependent of accuracy of the
components. The straightness and angles of these
even slight off would cause some problems. In a few
instances it wouldn’t be an issue, many cutting and
drills I could make accurately in the shop but since I
needed more time than the shop was open much of
this was made by hand and with a power drill. The
biggest fault came when fabricating the Y-Axis
connections Figure 56, Brackets
CNC Pumpkin Carver Adam J Frueh
34
Y-AXIS – CURVED RAIL AND LIFT
My biggest issue came after mounting these rail to
in the figure #. They were mounted with gorilla glue like
many other pieces in this build but I quickly noticed
how impossible it would be to align these with the linear
bearing on the lead screw platform. There was no trying
to make it work, I ended up breaking the blocks and lost
an expense linear bearing.
However I found a good solution I should have
thought about before. I removed the guess work with
aligning the rails and sampling lifted them with the new
platform seen in figure #. My biggest worry about doing
this before is the platform would simply rotate. Well it
was an easy fix to put a rail behind the platform to
prevent this.
Figure 57, gluing the rails.
After do this and connecting the y axis motor on
the roof the whole thing just came together and
had smooth motion.
Figure 58, Final lead screw platform
CNC Pumpkin Carver Adam J Frueh
35
X-AXIS – PLATFORM AND VICE
The X-Axis had its own issues. The first step was
constructing the mounting arms. They are made out of
sheet metal with hammered flanges to prevent
bending. The top arm only has a rotating point. The
lower arm has this but also holds the x-axis motor.
The issues with this build first arrised in aligning
the rails with the BRA rails and have them both
straight. All while trying to mesh the two with Figure 59 Top Mounting Arm
a central gear. After a very late night I discovered the
rails were crooked. This had set me back a whole day,
thou at least I knew what went wrong. Imagine trying
to sandwich these arms together, align a gear and
bracket the frame into the machine.
Even after I successful put the x-axis into the
chamber, I had discovered I was about half an inch
further back then I needed to be.
Figure 60, Bottom Arm
Figure 61, Front wall w/ rails Figure 62, Back Wall, w/ rails Figure 63, BRA in place
The rest was simple, attaching the gears train and the belt to the back and transferring the
motion to the front. With a drive shaft thou even this was misaligned
CNC Pumpkin Carver Adam J Frueh
36
Figure 64, Complete Assembly
Testing
Everything mechanical is in place to
work, however I can’t get the breakout
board to talk to the motors. I believe this is
because I don’t have a complete
connection with the driver or improper
wiring. I tired following the websites
instructions but they were made for another
set of electronics. These are very similar
but do have some differences. After
contacting the company they have had this
issue before and are working to release
instructions for this product. What they
told me is to have a professional look at it.
Figure 65, Electronic
Panel in place
CNC Pumpkin Carver Adam J Frueh
37
Conclusion
It’s hard to judge the failure of success of this project, since it’s uncomplete with no time
left. I plan to make this work, I might be able to take it to a train electrician, but it would be
simpler to ether wait for the company to release the instruction or to exchange the drivers and
other electronic for the parts they have instructions for.
On what I can judge, everything mechanical is running smoothly with no binding. Each
axis when manually moved act like they should. The biggest issue I see is alignment. The
curved rails are not centered to the vice’s center point. This would mess with the final image
and cause the CNC machine to run slightly awkward on a pumpkins surface.
Knowing what I know now I wouldn’t have constructed this out of wood. I would have
shoveled out the extra bucks to have the panels cut and drilled with precision out of sheet
metal like the original plan. Too much time was wasted in construction and alignment that
could have gone to figuring out the electrically work.
This project simply had two much for just me to do. I could have seen this split into a
two person project. This isn’t the end of the Pumpkin Carver, I plan to complete this in my
spare time and hopefully finish by this next Halloween. This might also be something a
future student would want to work on.
Works Cited
1. The safety of pumpkin carving tools. Marcus, Alexander M, Green, Jason K and
Werner, Frederick W. 6, s.l. : Elsevier Inc, 2004, Preventive Medicine, Vol. 38, pp. 799 -
803. 0091-7435.
2. Pumpkin carving as an exercise in design process thinking. Genereux, William E and
Lewis, Katrina M. Salina, KS : IEEE, 2014. 2014 IEEE Frontiers in Education Conference
(FIE) Proceedings. Vols. 2015-, pp. 1 - 7. 1539-4565.
3. Latchford, Teresa. Don't let pumpkin carving become scary. Newmarket Era-Banner.
7th, Oct 25, 2015, 0844-4072, p. 1.
4. Carlson, Meghan. Lifestyle: The Realistic Person's guide to Pumpkin Carving. Julep.
[Online] 10 15, 2014. http://www.julep.com/blog/halloween-how-to-pumpkin-carving/.
5. Hood-Daniel, Patrick and Floyed, James. Build your own CNC machine. New York :
Apress, 2009. p. 240. 978-1-4302-2489-1.
6. Hazards of Pumpkin Carving. Hankin, F M, Noellert, R C and Wilson, M R. United
States : American Family Physician, 09 1988, American Family Physician, Vol. 38, pp. 221 -
222. 0002-838X.
7. Dominic, Kelly. 10-Year-Old Purchases Pumpkin Carving Kit With Sharp Serrated Knife.
OPPOSINGVIEWS. [Online] 10 20, 2014. http://www.opposingviews.com/i/society/mother-
shocked-after-10-year-old-son-purchases-pumpkin-carving-kit-serrated-knife.
8. Brandeisky, Kara. Slate, future tense, The citizen's guide to the future. A Robot to Carve
Your Jack-o-Lantern for You. [Online] 10 23, 2014.
http://www.slate.com/blogs/future_tense/2012/10/23/punkinbot_from_brian_and_alex_vandi
CNC Pumpkin Carver Adam J Frueh
38
epenbos_carves_pumpkins_automatically.html.
9. Sorrel, Charlie. DIY CNC MACHINES JUST $390. www.wired.com. [Online] Gear, 1
10, 11. http://www.wired.com/2011/01/diy-cnc-machine-just-390/.
10. CHOP SHOP. Fabrication (CNC & Laser Cutting). Chop Shop. [Online] [Cited: 10 14,
2015.] http://chopshopcnc.com/services/cnc/.
11. Vlad. Dremel Body. https://grabcad.com/library/dremel-body, s.l. : s.n.
Appendix
A. RESEARCH
CNC Pumpkin Carver Adam J Frueh
39
B. SURVEY
Survey Questions Please fill out and return to Adam J [email protected]
Product: CNC Pumpkin Carver
This survey will be used to figure out the primary need and features desired for a product.
Please circle the appropriate choice
Freedom of movement Capabilities, would you want:
Continuous rotation Work only one side is all that’s
(Necessary for most Halloween designs)
Input of Design, would you want?
Computer driven, CNC Manual, control knobs
Work Environment, circle all that apply
Inside a store Workshop/Home Garage
Work Configuration
Countertop Standing Model
Does this need CNC need to be made FDA certifiable for what is carved
Yes or No
How much would you be willing to invest in such a device?
$400-500 $600-$750
How much would you be will to pay to use this in a department store or garden center?
$1-2/per pumpkin $3-4/per pumpkin
CNC Pumpkin Carver Adam J Frueh
40
C. QFD
Quality
Characteristics
(a.k.a. "Functional
Requirements" or
"How s")
Demanded Quality
(a.k.a. "Customer
Requirements" or
"Whats") 0 1 2 3 4 5
1 9 11.8 4.0 4 1 2 30.95
2 9 14.7 5.0 5 1 3 40.85
3 9 11.8 4.0 4 5 4 20.75
4 9 8.8 3.0 3 5 5 40.65
5 9 8.8 3.0 2 5 4 20.55
6 9 10.3 3.5 4 3 4 30.45
7 9 7.4 2.5 3 2 3 20.35
8 9 10.3 3.5 4 5 5 20.25
9 9 5.9 2.0 2 5 5 30.15
10 9 10.3 3.5 4 5 5 40.05
x
Deis
gn for least
am
ount of w
irin
g a
nd
ele
ctr
oic
ssm
art and e
asy
softw
are w
ithout
breakin
g the b
ank
▲
Fast, p
recis
e,
expensiv
e, m
ost likely
choic
e
Title:
Author:
Date:
Notes:
Adam J Frueh
Legend
Θ Strong Relationship 9
HOQ - CNC Pumpkin Carver
Chart A
xis
Valu
es
Powered by QFD Online (http://www.QFDOnline.com)
Our C
om
pany
Traditio
n P
um
pkin
Carvin
g
Pum
pkin
carvin
g k
its
Punkin
Bot
N/A
N/A
Not im
porta
nt fo
r this
proje
ct
4.0 6.613.7
Faste
r s
peed =
more
carved p
um
pkin
s
Pum
pkin
s w
ont
require h
igh torque
Sm
aller tool, D
rem
ial
siz
e
7 7 6
Sm
allest fo
ot prin
t
possib
le
Θ
11.5
3Moderate Relationship
Competitive Analysis
(0=Worst, 5=Best)
▲ 1
┼┼
Weak Relationship
Strong Positive Correlation
▼
Objective Is To Hit Target
Objective Is To Maximize
Positive Correlation┼
Negative Correlation▬
Strong Negative Correlation
▼ Objective Is To Minimize
Ο
┼ ┼
▼
┼ ▬
▼ ┼┼
▬ ┼ ▬
┼┼
┼ ┼ ▬
▼
▬ ┼
┼┼ ▼ ▬ ▬ ┼
┼▬ ┼ ▬ ▼
▬
Column # 1 2 3 4
Ro
w #
Direction of Improvement:
Minimize (▼), Maximize (▲), or Target (x)
Hydralic m
oto
rs
Weig
ht / Im
po
rtan
ce
11 12 13 14 15
Rela
tiv
e W
eig
ht
▲ ▲ ▼
5 6 7 8 9 10
▼ ▼
Softw
are
▲
5
Good torque a
nd
cost, b
ad m
ain
tance,
oth
er s
yste
ms r
eq.
Ο
Ο
9
502.9
Θ
Ο
Θ
Θ
Θ
▼ ▼
Weig
ht
Shie
lds/#
of safe
gaurds
▲
▲ Θ
Θ ▲ Θ
9 9
Θ Ο
9
Ο
Ο Θ Ο Ο ▲
286.8600.0 420.6 364.7 486.8
9 9
Ο
Ο
▲ Ο
9.0
9 99
9.6 8.3 11.1
307.4 401.5 176.5
44
Small deminsions/foot print
Tool size/resolution
Cheap
easy and simple to use
Safe
Ο
Θ ▲
Attractive housing
Ο
Θ
Ο Θ Ο Θ
Θ
10.0
4 5
9 9
394.1 436.8
Weig
ht should
be
min
imuiz
e
Θ Θ
Seal off w
ork a
rea
durin
g m
achin
ing
Ele
ctr
ic m
oto
rs
Driv
ing s
peed
Driv
ing torque
Tooling p
ow
er/s
ize
Expecte
d life
Dem
insio
ns
Ele
ctr
oic
syste
ms
Θ Ο Ο
Θ Ο ▲ Θ Ο
Θ Θ
Θ
Ο
Θ Θ Ο Ο
Relative Weight
Difficulty
(0=Easy to Accomplish, 10=Extremely Diff icult)
Θ Θ Θ
Θ
Θ Θ
Θ ▲ Ο
Max Relationship Value in Column
Target or Limit Value
Weight / Importance
Θ ▲ Ο Ο
No noise/minimum noise
Light w eight
Large range of surfaces and sizes
5 5 5
7.0 9.2
Ο
Max R
ela
tio
nsh
ip V
alu
e in
Ro
w
Ο Θ
▲ Ο
Fast cutting speed
▲ Ο Θ Θ Ο
Θ Θ
Our Company
Tradition Pumpkin Carving
Pumpkin carving kits
PunkinBot
N/A
N/A
CNC Pumpkin Carver Adam J Frueh
41
D. BILL OF MATERIAL/BUDGET OF MATERIALS
Table 3, bill of materials and costs
Part # Description Cost ($) qty
From SDP/SI A 1T 2-Y24042 Nylon Gear, 24 DP, 1.75PD, 5/16 bore, 20 PA 8.46 1 8.46
A 1M12-Y24 Nylon Rack, 24 DP, 12" stock length, 20 PA 3.51 1 3.51
A 1T 2-Y24060 Nylon Gear, 2.5 PD, 5/16 Bore, 24 DP, 20 PA 10.11 1 10.11
A 1T 2-Y24039 Nylon Gear, 1.625 PD, 5/16 Bore, 24 DP, 20 PA 8.07 1 8.07
A 6J 3-48DF03710 Polycarb, .2"(XL), 5/16 Bore, 3.056 PD 11.46 2 22.92
A 6Z 3-21DF03710 Polrcarb .2"(XL) 5/16, 1.528 PD 8.71 1 8.71
A 5C 9-0812 0.25" to 0.375" Coupling 17.77 1 17.77
A 6B 3-130037 Back Timing Belt, 130 Grooves, .2(XL) 7.06 1 7.06
A 6R 3-101037 X-axis Timing Belt, 101 Grooves, .2(XL) 7.78 1 7.78
A 1C12MY04B150 Metric Rack, 150mm Long, .4 pitch 17.93 1 17.93
A 1P 2MYD04045C Brass Insert, Gear, 5mm bore, 18PD, .4p 13.02 1 13.02
A 1B14-32064 Brass Rachet 7.14 1 7.14
A 1C14-04 Carbon Steel Pawl 3.78 1
A 6K 3-13DF03706 Small Timing Belt Pully 6.22 1 6.22
138.7
From McMaster 6655K35 Steel Thrust Bearing, 3/8" 3.43 1 3.43
9533T2 Linear Bearing, 5/16 14.58 2 29.16
91831A009 8-32 SS Nylon Locknut, 100/pack 5.59 1 5.59
92141A009 General Purpose Washers 2 1 2
95412A312 8-32 SS Threaded Rod, 8" 2.4 1 2.4
98804A104 8-32 SS Threaded Rod, 12" 3 2 6
9120K33 Zinc-Galvan Rod, 5/16 Dia, 3ft long 4.68 1 4.68
6061K423 14" Shaft, 3/8" dia 8.42 1 8.42
88985K93 HSS, 6"lg , Rod, .25 Diameter 4.27 1 4.27
9434K121 Spring, 5/pack 5.11 1 5.11
6435K13 3/8 Collar 1.91 1 1.91
6432K13 5/16 Collar 0.97 6 5.82
78.79
Essentrl Components HW-4 Hand Crank 13.22 1 13.22
from VXB KIT8405 3/8" V-Groove Guide Bearing, Sealed 3.95 6 23.7
608ZZ 8X22X7 bearings, 10/pack 7.37 3 22.11
KIT14240 5/16X7/8X5/16 Bearing 5.49 6 32.94
KIT8992 5/16 Bearing 3.77 2 7.54
KIT8993 3/8 Bearing 2.77 2 5.54
91.83
Build ur CNC 14 Teeth, .2"(XL), bore .25" 7.4 1 7.4
3/4 X 3/4 X 1/8 Alum Rail 1.2 8 9.6
Lead Screw, 3/8" 2.1 3 6.3
Anti Backlash Nut 27.95 1 27.95
Power Supply, 24 volts, 8.3 amp 43.96 1 43.96
NEMA 17 motor, 62oz-in 1/4" duel Shaft 19.95 1 19.95
NEMA 23 motor, 100oz-in 24.95 2 49.9
With Relay (Breakout) 28.5 1 28.5
2.5 AMP Motor Driver 45 3 135
Adjustable Rotary Limit Switch 13.95 1 13.95
Limit Switch, 6/pack 30 1 30
E-Stop 14.95 1 14.95
Motion 20 AWG CABLE 1.5 15 22.5
402.56
725.1
CNC Pumpkin Carver Adam J Frueh
42
E. SCHEDULE
TASKS 8/24
/201
58/
31/2
015
9/7/
2015
9/14
/201
5
9/21
/201
59/
28/2
015
10/5
/201
510
/12/
2015
10/1
9/20
1510
/26/
2015
11/2
/201
511
/9/2
015
11/1
6/20
1511
/23/
2015
11/3
0/20
1512
/7/2
015
12/1
4/20
1512
/21/
2015
12/2
8/20
151/
4/20
16
1/11
/201
61/
18/2
016
1/25
/201
62/
1/20
16
2/8/
2016
2/15
/201
6
2/22
/201
62/
29/2
016
3/7/
2016
3/14
/201
6
3/21
/201
63/
28/2
016
4/4/
2016
4/11
/201
6
4/18
/201
64/
25/2
016
Design I
Design Draft
Final Design Report
Design II
Proof of Design Agree (advisor)
Concepts/Selection (advisor)
3D Model - (name sub-assmby)
3D Model - (name sub-assmby)
Design Presentation
Design III
Manufacture
Test
Tech Expo
Project Presentation
Name(s)Project title
Sun - SatDesign presentation to faculty (12 min) Jan 27 – 31Design report to advisor Feb 3- 7Demonstration to advisor Mar 24-28 Tech Expo(Thur. Apr. 3)Project presention to faculty (15 min) Apr 7 - 11Project report to advisor for review before library submission Apr 14 – 18Library pdf file in BB (fall course link) Wed. Apr 23
Schedule Columns are by week starting with the first design task (Concept sketches/selection)Columns give datesTasks are broken into 1-2 week intervalsEach task line has 2 rows in the spreadsheet to allow for the actual interval to be addedDeadlines are typed as dates in the interval (earliest option)Deadlines match the MET and advisor requirementsOne deadline is the Proof of Design AgreementParts/materials are ordered as early as possible Readable (break into pages if needed)Informative heading
Table 4 Schedule
TASKS 8/24
/201
58/
31/2
015
9/7/
2015
9/14
/201
5
9/21
/201
59/
28/2
015
10/5
/201
510
/12/
2015
10/1
9/20
1510
/26/
2015
11/2
/201
511
/9/2
015
11/1
6/20
1511
/23/
2015
11/3
0/20
1512
/7/2
015
12/1
4/20
1512
/21/
2015
12/2
8/20
151/
4/20
16
1/11
/201
61/
18/2
016
1/25
/201
62/
1/20
16
2/8/
2016
2/15
/201
6
2/22
/201
62/
29/2
016
3/7/
2016
3/14
/201
6
3/21
/201
63/
28/2
016
4/4/
2016
4/11
/201
6
4/18
/201
64/
25/2
016
Design I
Design Draft
Final Design Report
Design II
Proof of Design Agree (advisor)
Concepts/Selection (advisor)
3D Model - (name sub-assmby)
3D Model - (name sub-assmby)
Design Presentation
Design III
Manufacture
Test
Tech Expo
Project Presentation
Name(s)Project title
Sun - SatDesign presentation to faculty (12 min) Jan 27 – 31Design report to advisor Feb 3- 7Demonstration to advisor Mar 24-28 Tech Expo(Thur. Apr. 3)Project presention to faculty (15 min) Apr 7 - 11Project report to advisor for review before library submission Apr 14 – 18Library pdf file in BB (fall course link) Wed. Apr 23
Schedule Columns are by week starting with the first design task (Concept sketches/selection)Columns give datesTasks are broken into 1-2 week intervalsEach task line has 2 rows in the spreadsheet to allow for the actual interval to be addedDeadlines are typed as dates in the interval (earliest option)Deadlines match the MET and advisor requirementsOne deadline is the Proof of Design AgreementParts/materials are ordered as early as possible Readable (break into pages if needed)Informative heading
CNC Pumpkin Carver Adam J Frueh
43
F. BUDGET
From my sources a small CNC machine can be built for at least $390. But can be as high
as $3000 dollars. But the average someone might spend is around $700-800, therefore I’m
setting my initial budget at $1000 dollars.
CNC Pumpkin Carver Budget
Raw Materials $300
Electrical components $250
Motors/parts $350
Odds and ends, special tooling $100
CNC Pumpkin Carver Adam J Frueh
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G. DATE SHEETS
NEMA 17
NEMA 23
CNC Pumpkin Carver Adam J Frueh
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Limit Switch dimensions
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H. DRAWINGS
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CNC Pumpkin Carver Adam J Frueh
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CNC Pumpkin Carver Adam J Frueh
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I. FABRICATED PARTS
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CNC Pumpkin Carver Adam J Frueh
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