PES INSTITUTE OF TECHNOLOGY BANGALORE – SOUTH CAMPUS

Hosur Road, (1K.M. Before Electronic City), Bangalore – 560 100 DEPARTMENT OF MECHANICAL ENGINEERING

SCHEME AND SOLUTION – III INTERNAL TEST

Subject :RAPID PROTOTYPING Semester : VIII

Sub. Code :10ME837 Section: A,B Name of the faculty : A. KHANNA

1. a) Explain PROMETAL Rapid Tooling Technique in detail.

b) What is the difference between Soft Tooling and Hard Tooling?

PROMETAL TOOLING TECHNIQUE

The ProMetal RCT equipment automatically builds sand molds and cores for casting metal directly from CAD data. Standard foundry industry materials are used, enabling easy integration of the new equipment into existing manufacturing and foundry procedures.

The large building volume and high building rate combine to make patternless production a reality for metal-based prototype castings and low volume production.

The molds and cores are built in an additive layer-wise fashion using a printhead, analogous to the ink-jet technology commonly used in desktop printers.

According to Dan Maas, Director of Business Development for ProMetal, "This revolutionary ProMetal RCT process allows design freedoms, which was never available to the casting designer or the foundry. Removing the requirements for parting lines, draft angles and providing undercuts. Moreover "Providing nested cores, spiral vents, volute shapes, integration of multiple components, in-situ cores, and unique rigging geometry to minimize turbulence are design features that are being utilized today by advanced companies." DIFFEREENCE BETWEEN SOFT TOOLING AND HARD TOOLING

Hard Tooling

Delivery of first article samples, 4 weeks (very simple parts) – 12 weeks (normal complexity) – longer for complex or parts requiring ceramic core tooling

(7 Marks) (3 Marks)

Delivery of production, 2 – 12 weeks after First Article approval.

Highest tooling expense

Lowest investment casting pattern cost

Hard tooling will have the longest life. Simple tooling will last for hundreds of thousands of parts. Complex tooling with slides and cores will wear over time but can generally be refurbished. This is not normally necessary for many years.

Yields the best surface finish and most consistent dimensional control.

Soft Tooling

Delivery of first article samples, 3 – 6 weeks

Delivery of production, 2 – 12 weeks after First article approval

Soft tooling is less costly than Hard Tooling

Pattern cost is higher than Hard Tooling. This is because the tooling will cycle slower due to the poor thermal conductivity of mold material

Life of soft tooling is limited. Life will depend upon the complexity of part. The more complex the shorter the life

Surface finish and dimensional control is not as good as Hard Tooling

A single SLA (stereolithography) or Objet pattern is generally used to make the tooling

2. a) Write benefits of Collaboration software tools in 3D printing.

b) Name various websites/web portals offering collaboration tools? COLLABORATION TOOLS

Collaboration tools like TeamPlatform web enabled cloud-based,

collaborative design and project management platform allows on

product design, engineering services and manufacturing companies

to share data and collaborate on 3D printing projects.

Autodesk 360 collaboaration tool focuses on features and cloud

services that can help you improve the way you design, visualize

and share your work with others; but TeamPlatform's goal is to help

people and companies work together much more easily and quickly.

It focuses on connecting businesses, sharing and collaborating

designs with the added of workflow tools.

WEBSITE / PORTALS

1. imaterialize 2. Shapeway 3. TeamPlatefor 4. Autodesk 360

(6 Marks) (4 Marks)

3. a) Explain with neat sketch DMLS rapid tooling process? (6 Marks)

b) Give its benefit over traditional process? (4 Marks)

Direct Metal Laser Sintering Utilizing the DMLS rapid tooling process, metal parts of the most complex geometries are built layer-by-layer (down to 20 microns) directly from 3D CAD data. Parts built using DMLS have excellent mechanical properties equivalent to wrought materials, high detail resolution, and exceptional surface quality. The metal powder is melted entirely to create a fully dense, fine, homogenous structure. Unique geometric freedom of design enables DMLS to form cavities and undercuts, which with conventional machining methods, can only be produced with great difficulty, if at all.

DMLS produces parts that are extremely high quality and can be built in a matter of hours or days rather than weeks. The

ability to generate functional metal prototypes in short order radically impacts design processes, accelerating design cycles and time to market.

Depending on size and geometries, in some cases the turnaround time for a part can be as little as a few hours. Benefits Over Traditional Processes Additionally, when a part needs to be tested and re-designed over and over, the lead time for receiving a traditionally tooled part can create a large bottleneck in the final production process. Furthermore, these parts can undergo functional testing in the environment for which they were designed. This technology delivers unlimited potential for engineers to create previously impossible solutions, embracing a new era of design-driven manufactureing.

4. a) Write briefly about MAGIC, SOLID VIEW and MIMICS software tools. (4 Marks)

b) Write the process of design and manufacturing a Jewellery product (6 Marks) using RP tools, software and techniques? , SOLID VIEW and MIMICS software tools:

MIMICS

Mimics is software specially developed by Materialise for medical

image processing. Use Mimics for the segmentation of 3D medical

images (coming from CT, MRI, micro-CT, CBCT, 3D Ultrasound,

Confocal Microscopy) and the result will be highly accurate 3D

models of your MAGIC patient’s anatomy. You can then use these

patient-specific models for a variety of engineering applications

directly in Mimics or 3-matic, or export the 3D models and

anatomical landmark points to 3rd

party software, like statistical,

CAD, or FEA packages.

Use Mimics to:

Easily and quickly create accurate 3D models from imaging data Accurately measure in 2D and 3D Export 3D models in STL format for additive manufacturing Export 3D models to 3-matic to optimize the mesh for FEA or

CFD

MAGIC

Magics, a user-friendly data preparation software package and

STL editor, can guide you through every step of your Additive

Manufacturing or 3D

Printing workflow.

1. Import Files

With Magics, you can

import nearly all file formats and native color information, and

stay in control of your original data.

2. Fix and Prepare STL Files

The STL editor in Magics

allows you to correct problems, as well as create watertight data

and shortcuts to suit your workflow, all in a user-friendly

interface. STL File fixing includes repair of flipped triangles, bad

edges, holes and other defects.

3. Enhance and Edit Data

With Magics, you can also take your designs to the next level: add

logos, serial numbers, and hollow parts; apply textures; and

perform Boolean operations and

advanced cuts.

4. Prepare the Platform

Magics has the tools you need to duplicate parts, orient them in an

ideal way, and create no-build zones.

SolidView/Pro RP is the most robust of the SolidView family of products

and is designed for companies doing their own rapid prototyping work.

SolidView/Pro RP offers all SolidView/Pro features as well as advanced

rapid prototyping tools; compound cutting, file repair, z-correction,

shelling, offset, and automatic or manual object layout. Optional CAD

formats and network licenses are also available for SolidView/Pro RP.

The following features are included with SolidView/Pro RP:

View and Print STL, SVD, and SolidWorks formats

Print STL, SVD, and SolidWorks formats

Measure SVD, STL, and SolidWorks formats

Create PLY files

Create SVD files

View 2D drawings

Translate

Scale

Rotate

Mirror

Copy

Combine

CAD Formats Available

Network Licenses Available

Cut (cross-section)

Shell

Repair

Manual RP Layout

Auto RP Layout

Jewellery Manufacturing Rapid Prototyping (RP) and Additive Manufacturing (AM) techniques are usually widely used into those sectors into which complex shapes and relatively low production are required. Due to its peculiarities Jewellery industry is perfectly matching In many manufacturing companies CAD data are then transferred to Rapid Prototyping equipment which allows for fabrication of pattern directly from the CAD data . The RP processes, mainly represented by wax 3D printers and stereo-lithographic apparatuses, are most of the times fully integrated into the traditional process, either to produce the master model or to produce replicas to be directly assembled on the tree. This last process, commonly referred to as “direct casting” is

highly interesting opening several possibilities in terms of shapes and production flexibility Flow Chart for Jewellery Making is as follows

5 a) What are various part building errors in RP Technologies? (5 Marks)

b) Explain parameters for dimensional accuracy of 3D component? (5 Marks) SEVEN Part Building Errors in RP Technologies are as follows

1. The part design has thin features or walls that are less than .030” for standard resolution or .015” – .020” for high resolution machines. Due to the ―layer by layer‖ approach of the additive manufacturing process, anything smaller or thinner that this will often times not build and will not be present in the final model. Pay very close attention to raised or recessed logos and areas of small text, ―knife edge‖ features which taper down to zero thickness, and curvy sections of any design where thickness can fluctuate.

2. The native CAD model is converted to .STL format with a very low resolution, resulting in heavy faceting in the model. If the resolution of the .STL file is too low, the model will be faceted instead of having smooth surfaces and curves. This can be quite common and produces unattractive parts. Typically, to achieve a smooth finish on a model there should be an edge-to-edge distance of less than .020‖ between facets on the .STL file. Check the parameters on the native CAD program being used to determine the best method

of exporting acceptable .STL files.

3. The original CAD data has numerous unstitched surfaces (rather than solids), resulting in errors when converting to .STL format. Make sure that the surfaces in the original CAD model are ―water tight‖, in that only solids are modeled. The .STL file can also be inspected to ensure that all dimensions, part volume, and surface area all appear to be correct.

4. The part design has an enclosed hollow space from which support and build materials cannot be removed. Any enclosed hollow void in the design will contain support materials which cannot be removed through the finishing process. This area may also be filled with unused resin or powder depending on the selected prototyping process. Consider filling in voids to be solid, building the design in halves to allow access to the enclosed space, or adding a hole of some kind in the model to allow for the removal of the support materials.

5. Assemblies, threads, and mating features are designed with improper clearance. The standard tolerances for most additive manufacturing processes start at +/- .005‖ and compound from there as the design increases in size. It is not uncommon for first time customers to receive parts that, while within the published tolerances of the manufacturing process, do not ―fit together‖ or mate up as intended. Typically, there should be a .015‖ – .020‖ clearance between mating parts, which is different from what is required for traditional injection molding. This is an important point to remember when the success of the project depends on how well different designs mate up or assemble with one another.

6. The design includes a living hinge which needs to function. Living hinge designs on most parts produced via additive manufacturing don’t typically function as intended. The build material involved is often too rigid, especially in such a thin section, and will break. While there have been a few materials developed that look to address this need (the Duraform EX material using the SLS process can often work well), expect limited usage from a living hinge design produced via additive methods.

7. The units of measurement for the .STL file differ from what was intended. Double check the .STL files properties to ensure that the correct unit of measurement is selected. This is especially true when there is more than one design with varying units of measurement being built together. Some CAD packages also have default settings where .STL files may be exported in a different unit of measurement from what was used during the design process. When there is a tight time line and the project is on the line, it can be difficult to see the comedy in dramatically oversized or undersized parts as they come out of the box.

Keep these seven common mistakes in mind when considering any

additive manufacturing project. Be careful to confirm the integrity of the original CAD data, and be mindful of living hinge designs, enclosed or trapped hollow spaces, clearance between mating features, and any features or walls that are smaller or thinner than .030‖. After exporting the .STL file from the native CAD file, take time to confirm that the overall resolution of the file is sufficient and that the selected units of measurement are correct.

Parameters For Dimensional Accuracy of 3D Component Dimensional accuracy of a component part represents the degree of agreement between the manufactured dimension and its designed specification. It is the most critical aspect to ensure dimensional repeatability of manufactured component parts. The resolution and accuracy of porous 3DP samples are determined by many factors, including print head resolution, material used, printing delay, build orientation, geometric features and their topology, post treatment procedures, precision of the linear stage positioning, binder drop volume, binder–powder interaction, particle size and last but not least, the layer thickness. Unfortunately, the efforts to determine these effects are often hampered by the limitations set by the commercial printers. In order to achieve a breakthrough in 3DP for scaffold engineering, accuracy (the mismatch between the model and the 3DP specimen) and resolution (smallest feature size) need to be substantially improved .

6 a) Write with neat sketch quick cast process? (7 Marks)

b) Name the industry were this techniques is used successfully. (3Marks) Quick Cast Process QuickCast® Investment Casting Patterns are accurate, consistent, strong, fully drained and completely sealed patterns that are 10 to 35% lighter than those built with other polymers and ordinary build styles. Advantages and Industries Using This Technology

Lower Cost

Lower Cost is achieved with our SC 1000 material. 1) Our cost is lower—we pass along the savings. 2) This material is more stable, reducing the over-all cost of operation. 3) Patterns made with SC 1000 demonstrate higher yield both in SLA part building and more importantly during flash firing. We offer aggressive pricing to encourage higher volumes; often demonstrating that a tooling/wax approach is more expensive and a higher risk.

Lighter Weight

Lighter Weight patterns are sought after by knowledgeable foundries. These QuickCast® patterns are up to 35% lighter than conventional stereolithography patterns. This translates directly to higher yield in the casting process. Proportionately less ash is produced and thermal expansion forces are minimized during flash firing.

Production Capacity Production Capacity is a given at Solid Concepts. We have twenty five SLA Systems including both large (20″ cube build envelope) and smaller (10″ cube) sized machines. Capacity translates to better on time delivery. All of these systems are kept at peak performance by regular maintenance. Large Part ExpertiseLarge Part Expertise has come with over twenty years in the business. We take on large projects that others cannot or will not. We have assembled and inspected even larger parts. For large parts, experience with custom assembly fixtures and large part packaging is a must.

New Build Style New Build Style and SC 1000 make these patterns truly unique. This build style and photopolymer combination has already been approved by most major US foundries. This proprietary build style offers complete internal draining and excellent final surface sealing.

7 a) What is process optimization important in RP Technologies? ( 6 Marks)

b) What’s part building error? How you can control it? (4 Marks)

Rapid prototyping (RP) has evolved as frontier technology in the recent times,

which allows direct transformation of CAD files into functional prototypes where it

tremendously reduces the lead-time to produce physical prototypes necessary for

design verification, fit and functional analysis by generating the prototypes directly

from the CAD data.

Part quality in the rapid prototyping process is a function of build parameters such

as hatch cure depth, layer thickness, orientation, hatch file, hatch spacing and part

characteristics. Thus an attempt was made to identify study and optimize the

process parameters governing the system which are related to part characteristics

using Taguchi experimental design techniques-quality.

The part characteristics can be divided into part physical characteristics and

mechanical characteristics. The physical characteristics are surface finish,

dimensional accuracy, distortion, layer thickness, hatch cure, and hatch file

whereas, mechanical characteristics are flexural strength, ultimate tensile strength

and impact strength.

Thus, the paper proposes to characterize the influence of the physical build

parameters over the part quality. An orthogonal array of experiment was

developed which has the least number of experimental runs with desired process

parameter settings and also by analysis tools such as ANOVA (Analysis of

Variance). Establishment of experimentally verified correlations between the

physical part characteristics and mechanical part characteristics to obtain an

optimal process parameter level for betterment of part quality is obtained. The

process model obtained by the empirical relation can be used to determine the

strength of the prototype for the given set of parameters that shows the

dependency of strength, which are essential for designers and RP machine users.

8 Write notes on a) Build Orientation

(5 Marks) b) Layer Thickness

(5 marks)