lesson39 usage of assembly cuts

8/14/2019 Lesson39 Usage of Assembly Cuts

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11/6/13 www.sharptechdesign.com/Tutorials/ProE_Fundamentals_WF2/WF2_Lesson39.htm

www.sharptechdesign.com/Tutorials/ProE_Fundamentals_WF2/WF2_Lesson39.htm

Lesson Objective:In this lesson, we will learn how to create exploded states, complete with

offset lines.

USAGE OF ASSEMBLY CUTS

Lesson

39


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www.sharptechdesign.com/Tutorials/ProE_Fundamentals_WF2/WF2_Lesson39.htm 2

There are a variety of reasons to create cuts in the context of an assembly. The most common are:

Cut-Away Views You create a cut that removes volume from some or all of the components inthe assembly. Unlike a cross-section, which will remove volume from all of the components when

you set the visibility to view the cut-away, an assembly cut allows you to selectively pick which

components are affected.

Holes/Cuts in Weldments Adding a hole pattern or cut to an assembly that represents a singleweldment. The ability to create the holes in the individual parts is minimized, because of

dimensional references that may or may not exist.

CUT-AWAY VIEW

We will work with the stacker assembly that we created in Lesson 38 to demonstrate cut-away views.

Open up this assembly, and it will look like the following.

We want to make a cut that removes half of the volume from all of the components except the stempart. Before we do this, however, let us look at a cross-section for this part.

To do this, go to View, View Manager. When the view manager opens, click on the Xsectab. Create

a new cross-section called Cut_Away, and use the ASSY_RIGHTdatum plane as our reference (pick it

from the model tree).

Once you have created this cross-section, double-click on it. We see the following.


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As you can see, the cross-section view removes half of the stem as well as the rest of the components.We want to see the entire stem.

Therefore, we will use an assembly cut. First , close out of the view manager, and go into the layer tool.

Hide all_Defaultslayers except for the assembly itself. Your assembly should look like the following

with datum planes visible.

Now, click on the Extrudetool. Down in the dashboard, you will notice that the Remove Material icon

is grayed out. The reason for this is that any solid feature created in assembly mode can only remove

material, not add material.

Now, click on the Placementslide-up panel. It looks like the following.


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We can either select a sketch feature in the assembly, or create a sketch. We will click on the Define

button. For a sketching plane, select the ASSY_TOPdatum plane, and face the ASSY_RIGHTplane

towards the Right.

Inside the sketch, select the outermost circle (both halves) as sketching references. Then, sketch the

following rectangle. Be sure to impose a tangent condition with the side, and snap to the top and bottom

of the circle.

Finish out of the sketch, and make sure you go to the Options slide-up panel and select Through All

for both directions, as shown below.

Finally, go to the Intersectslide-up panel. It looks like the following.

By default, all components in the path of the cut are going to be listed in the window. In this case, all

seven parts are listed. We will start by un-checking theAutomatic Updateoption at the top. This

allows us to select ively add/remove models from the list. We will scroll to find the STEMmodel, and

right click on it. Select Removefrom the list of options, as shown in the next figure.


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Click on the green check mark to finish this extrude feature, and we will be left with the following.

The Stem part is completely unaffected by this cut. The other models are only cut away in the

assembly. If you open the Base or any of the rings, they still are whole. We will show something

different in the next section. To turn off the cut-away, either delete the extrude feature or suppress it.

Save and close this assembly. We will come back to it in the last lesson.

WELDMENT CUTS/HOLES

The other common usage for assembly cuts would be in an instance where you can not easily define a

hole or cut in a single part that may affect a group of parts. A good example might be a welded frame

that will get items mounted to it. The spacing of the holes, as well as the locating dimension for the

holes is usually determined after the frame is completely welded. But, for manufacturing reasons, we

need to model the members of the frame separately and use an assembly to define the overall frame.

Change working directories over to the Weldmentfolder, and open the assembly entitled


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Welded_Frame.asm . It looks like the following.

If we expand the model tree, we can see the product structure as follows:

The overall frame (gray bars) is welded together. The plate on the side (green) will be bolted onto the

frame. In order to ensure that our bolt holes line up perfectly, we could do a number of things. Perhaps

the cleanest would be to develop a skeleton for the interface points, and develop the weldment and the

plate from this information.

In this case, we are working with existing assemblies, so we only have two choices. We can go into

each model, create separate holes/cuts and then build in relations between components to determine

the location in case a change is made. This is a perfectly acceptable way of doing it, but creates a lot o

book keeping. It also assumes that each hole can be manufactured off of existing references in the part

file. In our assembly, we want to locate the holes from the extreme ends of the assembly, so it wont

work at the part level without adding extra datum planes or surfaces to capture the envelope of theassembly.

Therefore, we will create the cut at the assembly level, and then discuss how we might be able to

transfer that information into the parts (if required).

Creating the Cut

Click on the Extrudetool once more. Define the sketch, and use the front of the plate as a sketching

plane, and point the ASSY_RIGHTdatum plane towards the left. In sketch mode, change your display

to a hidden line mode. If your sketch doesnt automatically pick references, select ASSY_RIGHTand

ASSY_TOPfor sketching references.


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Zoom in on the upper left corner, and sketch the following:

Now, pan over to the upper right corner and sketch two more circles making sure to align the centers

where applicable, and dimensioning where necessary.

In the lower right corner, sketch two more circles, as follows:


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Finally, in the lower left corner, finish sketching the last two circles, as shown. NOTE: You shouldnt

need any dimensions for these holes, as the centers should line up with existing circles or references.

Zooming out, our entire sketch should look like the following.


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Finish out of the sketch. For a depth option, pick on the To Selecticon (the one with the red), and pick

the following surface.

Now, we will click on the Intersectslide-up panel. It currently looks like the following.


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We can see four MAIN_BARmodels listed. In reality, the holes that we are creating are not going to

intersect these models, so we will remove them. To do this, un-check theAutomatic Updateoption, and

then right click on each of these bars to remove them.

We are left with two SIDE_BAR, two MID_BAR, and one SIDE_PLATE components, as shown in the

next figure.

One other thing we can see in this window is that each component has a value of Top Level, in the

Displaycolumn. This means that the cut will only show up in the top-level assembly where it is created.

We will right-click on each of these models in the list and change the option to Part Level. The

intersect window will look like the following when we do this.

Click on the green check mark to complete this extrude feature, and you will see the following on your

model.


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From this figure, we can clearly see holes on all of the mid and side bars. The reason for this is the cuthas been translated into the actual part file. If we open the SIDE_BARcomponent, for example, we see

the holes.

In the model tree, it indicates theAssembly Cuts, as shown in the following figure.

If you try to edit or edit the definition of these features in the part itself, you will find that you can not.

You have to go back to the assembly to edit them. This is intended functionality.

If we had kept the models at the Top Levelscope, this is what we would have seen at the assembly

level.


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We can see that the holes are only on the side with the plate. All other Side and Mid bars are

unaffected. If we open up the same SIDE_BARmodel, we dont see the holes, and the model tree does

not list the assembly cut features.

The advantage of placing the visibility of the holes at the part level is that we can detail out the part in

drawing mode and dimension the holes accordingly to perform the drilling at the part level. Of course, if

this had been the original intention, we might have wanted to just create them as part cuts, and then tie

them together with relations at the assembly level.

The disadvantage of placing the visibility of the holes at the part level is that the model being cut will now

have the holes in every instance that is used in the assembly, as we saw in our model. The work-around

to this would be to model completely different bars for the side with the plate than what is on the rest of

the frame. This creates more models than we really need. Of course, had we needed to add a plate tothe other side, we can now just assemble in one more with the bolts and nuts and we wont have to

necessarily cut additional holes out.

LESSON SUMMARY

Assembly cuts are great for creating cut-away views that cant be done with cross-sections, or for

creating cuts/holes in an assembly and showing the visibility at the part level.

Be sure to look at the list of models that the cut will intersect, and remove any models that you dont

need in the list.


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EXERCISES

Open up the model entitled Shelf.asm. It will initially look like the following.

For this exercise, we need to drill holes to screw the pieces together. The following figures show the

locations for the holes. We also need these holes to appear at the part level to be able to detail out the

individual boards.


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lesson39 usage of assembly cuts

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