Mechanism assembly

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Mechanism Assembl
CimatronE 8.5 Tutorial

CimatronE 8.5 Mechanism Assembky i

Table of Contents

Mechanism Assembly ......................................................................................................... 1 Stage1 Early Preparation ................................................................................................. 2 Stage2 Create the Assembly .......................................................................................... 12 Define the Mechanism assembly ................................................................................... 17

Stage 3 Define the main part ...................................................................................... 17 Stage 4 Define the Parent/Child Relationships .......................................................... 18 Stage 5 Define Interchangeable parts......................................................................... 20 Stage 6 Catalog Filtering Relations............................................................................ 24 Stage 7 Formulas........................................................................................................ 30

Stage 8 Save the Mechanism assembly ......................................................................... 34 Stage 9 Load the Mechanism assembly......................................................................... 36

ii Mechanism Assembky CimatronE 8.5

CimatronE 8.5 Mechanism Assembky 1

Mechanism Assembly

In this exercise we will see an example of the Mechanism Assembly, by creating a Slider mechanism assembly.

Stage 1: Early preparations

Stage 2: Create the assembly

Stage 3: Define the Mechanism assembly

Define the main part


Define the Parent / Child relationships


Define Interchangeable parts


Catalog relations


Apply Formulas

Stage 8: Save the Mechanism assembly

Stage 9:Load the Mechanism assembly:

2 Mechanism Assembky CimatronE 8.5

Stage1 Early Preparation

In this stage early preparations are done (in general, it is an optional stage depending upon the mechanism assembly you are creating).

In this example, it is necessary to add some features to the slide core Slide Z 180, such as angle and plane, for placing the leader pins later on and to allow the user easy and full control over these parameters. We will define new dimensions to be saved later in the catalog


Note that the Slide core in the Hasco catalog already contains these changes.

Define the Angle pin position Copy the catalog part Training Slide Z 180.elt into your “standard parts” catalog

(C:\Cimatron\CimatronE\Catalogs\Standard Parts).

Select Tools/Edit Catalog Master – select the part.

The dimensions we are now going to add will be saved later in the catalog as:

'Pin angle': a (18 º) and 'Pin offset': dX (24)


Show the hidden Main Planes and create a Sketch on the YZ plane. Sketch a line with 18 º declined to the vertical face and 24mm distance from the UCS in the Z direction.

Defining the position for the “2 pins Slider” Define the position of the two other pins by a Symmetry- Sy parameter (17)


Create the plane (“Defined by”) from the line in the X direction.

Create a sketch on the previously created plane. Using the symmetry line, sketch two lines at a distance of 17.


Control the height of the angle pin and the locking heel Pin offset dZ (20)


Create a parallel plane to the top face of the slide core.

Control the height of the locking heel.

Clearance C (0)


Create “plane parallel” (delta=0) from top face of the slide core

Save the catalog part Select Save, the Save Catalog Part dialog is opened.

Select the Advanced option to display the full table.


Add the new dimensions:

1. Pin angle a

2. Pin offset dX


3. Symmetry Sy

4. Pin offset dZ


5. Clearance C

To add a new record to the table, select the relevant dimension from the graphic area.

These parameters should be saved as “Free dimensions”.

Press the Next button.


Adjust the dimensions in the table lines according to the general dimensions of the part.

Select Next and then Finish.

Stage2 Create the Assembly

Create the Assembly In this stage we will create the assembly; add relevant parts, set connections and defined relations.

Parametric relations can be defined only within non catalog parts. If the assembly contains relations between catalog parts it cannot be saved as an assembly catalog mechanism. This limitation is to avoid cyclic dependencies in the assembly and regenerations problems.

Parametric relations are allowed between standard parts, or between a standard part and a catalog part (the parametric relation must be added to the standard part).


Unpack the file Slider Mechanism Z 180.ctf

Open the example assembly Slider Mechanism Z 180;

The example assembly contains the needed catalog parts.

Note that the Assembly mechanism should not contain sub-assemblies.

Interchangeable parts Notice the interchangeable parts such as the Guide strip Z 185 and the Guide strip Z 185W.

Hide the Guide strip Z 185. Note that the Guide strip Z 185W is in the same location.


In this example, both Guide strip Z 185 and the Guide strip Z 185W were added to the assembly.

We will define these parts as interchangeable parts; meaning that these are parts that can be interchanged with one another when loading the assembly from the catalog.

The assembly should contain all optional (interchangeable) parts that you intend to have. Off course when adding the mechanism assembly from the catalog, only the relevant part of the interchangeable will be opened and the other will be in suppress mode.

Connections between the parts Note the connections between the parts in the assembly.

Edit the connection Concentric69 of the purple guide pillar.

The purple guide pillar is Concentric to the line defined in the slide core.

Edit the connection Coincident70.


The center of the top face is coincident to the plane (Pin offset dZ).

Add a “non-catalog” part to the assembly Add a new part lower wear plate. Place the part on the assembly UCS.

In the new part, create main planes.

Create a rectangular sketch on the XZ plane. Take a reference from the width of the slide core Z 180. The length is 100mm.


Extrude the sketch to delta 5 mm.

Note that Parametric Relations can be defined only within non-catalog parts. The catalog part can be the server while the non-catalog part is the client.

Create Parametric Relation Create a parametric relation between the lengths of the new wear plate and the length of the Slide core

Z180.

L wear plate = 1.5xL slide.


Save the assembly.

Define the Mechanism assembly

Stage 3 Define the main part

Define the main part Define the Mechanism assembly; this is done in a few stages:

Define a Main Part, define the Parent / Child relationships, define Interchangeable parts, Catalog relations and Formulas.

Defining a Main Part to the Mechanism assembly is a mandatory stage; all the other stages are optional.

The Main Part will always be in the assembly and cannot be dependent in other parts. Only one part can be the Main Part.

Activate the main assembly. From the main menu, select Catalog / Create Mechanism Assembly / Main Part.

Select the slide core and press OK.

Mechanism Assembly operations can only be performed on an assembly once a Main Part has been defined.


Stage 4 Define the Parent/Child Relationships

Define Parent This step, enables you to create groups of parts that will be suppressed/unsuppressed together. It also will determine the "direction" of Catalog Relations (CR) between the parts.

For example, if there are screws and dowel pins that are children of the guide strip, this means that suppressing the guide strip (the parent) will also suppress the screws and pins (the children). It also means that the dimensions of the screws and pins will be controlled by the guide strip and not vice versa.

From the main menu, select Catalog / Create Mechanism Assembly / Parent/Child

Select the Guide strip Z185 in the left pane and press the New Parent button.


A new parent is added to the right pane.

Note that:

Instances of the same part can be parents of different children.

Instances of the same part can be children of different parents.

Define Child Select the parent, then the two instances of “Cap screw Z30” in the right pane.

Make sure you select the screws which belong to this Guide strip.

Press the Child button.


Complete the Child/Parent relationships so the dialog appears as follows:

Select OK.

Stage 5 Define Interchangeable parts

Stage 5 Define Interchangeable parts

Interchangeable Groups

This step enables you to define parts as Interchangeable Parts. These are parts that can be interchanged with one another when loading the assembly from the catalog.

For example if a slider assembly has 2 types of Locking Heel, one of the 2 types can be selected when loading the assembly from the catalog. The one that is not selected will be suppressed.


Define Interchangeable parts From the main menu, select Catalog / Create Mechanism Assembly / Interchangeable Parts.

Note that a Child part cannot be an interchangeable part (only a Parent and a free part).

Select the 1st Guide strip Z185W in the left pane of the dialog (or from the display).

Press the New Group button.

The selected part is moved to the Groups pane under a new group.

Type of right guide strip Rename the group to Type of right guide strip.

Select the Type of right Guide Strip group in the right pane.

Select the equivalent Guide Strip Z185 part in the left pane.


(If selecting from the display area, use hide/show to make sure you select the right strip).

Press the Forward button.

The icons displayed in the Groups pane are:

Group

Parent part

Free part

The part is added to the group and becomes one of the interchangeable parts in that group.


Complete the Interchangeable part definitions Complete the Interchangeable part definitions so the dialog appears as follows:

Select the middle Guide Pillar as the single Drive Pin and the two outer Guide Pillars as the pair of Drive Pins.

Multiple parts can be defined simultaneously.

Select OK.


Stage 6 Catalog Filtering Relations

Catalog Filtering Relations This step enables you to create Catalog Relations (CR) between components in the Mechanism Assembly. These relations use the parent/child relationships and create filtering rules on the parts in the Mechanism Assembly. These filtering rules enable the catalog to be filtered and only display a specific part size that meets the defined relations.

This means that if, for example, the length of a screw is proportional to “rail height” when the assembly is regenerated, the screw table display will be filtered to this specific screw length.

From the main menu, select Catalog / Create Mechanism Assembly / Catalog Filtering Relations


1st area displays the parts according to the following hierarchy of interchangeable type groups, then parents and children below. Free parts and the Main Part are also in the first level.

2nd area displays the Component catalog records.

3rd area displays the relation expression you are currently creating.

4th area displays the list of already defined relations.


Crate a Catalog Relation We will now create a “catalog relation” between the Guide strip height (the client) and the Slide Z180

height (the server).

Select one instance of the Guide strip Z185. Select the length h2 in the Component record field and hit the button Attach dimension.


The dimension appears in the Expression Editor left pane.

Note that:

• Only Primary Dimensions can be selected as “client dimensions”.

• Parts can be selected from the display area.

Expression Set the “Equal” sign “=” from the list:


Select the Slide Z180 (as the server). Select the h1 dimension from Component record and attach it.

Add -1 to the expression. ( h1-1).

Press the confirm relation button to submit the new expression into the Relations list.

Note that when the assembly is loaded from the catalog, the table of the Guide strip will be filtered to display the items with the proper height.


Complete the creation of Catalog Relations Complete the creation of Catalog Relations according to the following table.

Make sure you create the relation to the real parent. For example the cap screws should be related to their guide strip, not the 2nd strip.

Guide strip Z185: h2 = Slide Z180: h1-1 Guide strip Z185: l1 > Slide Z180: l1 Cap Screw Z30: d = Guide strip Z185: d2 Cap Screw Z30: l = Guide strip Z185: h2 Guide strip Z185W: h2 = Slide Z180: h1-1 Guide strip Z185W: l1 > Slide Z180: l1 Cap Screw Z30#1: d = Guide strip Z185W: d2 Cap Screw Z30#1: l = Guide strip Z185W: h2 Locking heel Z182: b1 <= Slide Z180: b1 Wear plate Z1821: b1 = Locking heel Z182: b1 Wear plate Z1821: h2 = Locking heel Z182: h1 Countersunk socket head screw Z33: d = Locking heel Z182: d1 Countersunk socket head screw Z33: l = Locking heel Z182: t1+4

Press the appropriate arrow to move a relation up or down the list.

Select OK button to execute the process and exit from the dialog.


Stage 7 Formulas

Formulas This step enables you to define formulas based on the dimensions of the parts in the assembly. These formulas supply the necessary information when loading the Mechanism Assembly from the catalog and enable you to choose the best combination of parts.

This means, for example, when loading the Slider mechanism from the catalog, you are able to verify that the stroke of the slider is long enough to release the "undercut". The formula will determine the stroke from the length and angles of the pins.

From the main menu, select Catalog / Create Mechanism Assembly / Formulas.

Free Variables

The upper section of the dialog is used to define Free Variables. These variables do not exist in the model and you can define them and use them in the formulas. If no free variables were defined, the formula will only include dimensions from the model.


Formulas

The lower section of the dialog is used to define Formulas.

New Variable Press the New Variable button.

A new variable with a temporary default name is added to the Free Variable section.

Rename the new variable. Enter a description and a default value.


New Formula Any mathematical signs and Free Variables can be added to the formula.

Press the New Formula button.

A new formula with a temporary default name is added to the Formulas section.

Rename the new formula Slider Width (the formula is the calculation of the entire Slider width).

Add dimensions to the formula adding the free variable name, i.e. W.

Multiply the Guide Strips Width (W) by 2 and type "+".

From the display area pick the width of a slide part to add it to the formula.


Every picked dimension from the display area is added to the formula.

Click OK.


Stage 8 Save the Mechanism assembly

Save the Mechanism assembly Save an assembly as a Mechanism Assembly. This creates a Mechanism Assembly from an assembly of catalog parts.

Note: The Save as Mechanism Assembly option is only available once a Main Part has been defined for the Mechanism Assembly.

Select File/ Save as Mechanism Assembly and add the following pictures Hasco Slider 1.jpg and Hasco Slider 2.jpg picture.

Select OK.


Save the catalog.


Stage 9 Load the Mechanism assembly

Load the Mechanism assembly Open a new assembly. Save the Assembly.

Select the Add from catalog icon.

Select the saved Mechanism Assembly from the Catalog.

Save the assembly.

Select Place by UCS and select the Assembly UCS.

The Mechanism Assembly is now displayed in preview mode. The first option in every group of interchangeable parts is initially displayed.


Edit Parameters Select Edit Parameters

The Mechanism Assembly Adjustment dialog is displayed.

Notice the following buttons:

Select this button to change groups

Suppress

Unsuppress

Filtered tables


Suppress Note that suppressing a parent automatically suppresses the children.


Change interchangeable group Change the interchangeable group; select No. of Drive Pins (2).


Press the Expand Advanced button.

Change some of the free parameters to see the effect in the preview.

Press the Apply button to view the result.

Change the angle back to 18.

Catalog table Change values of parent parts and see how the system displays the filtered table with the relevant parameters only.

If Catalog Filtering Relations have been define for this part, the catalog table will be filtered and only the appropriate parts are displayed in the table. If necessary, you can cancel the filter and the whole catalog table (for the part) is displayed.


Open the table of the left guide strip. Notice the relevant rows in the table.

Change the size of the slide core from Z180-20*63*63 to Z180-32*100*80.


Reopen the table of the left guide strip. Notice that the relevant rows have been changed according to the new slide core size.

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Mechanism assembly