DESIGNING ASSEMBLIES

(Or, how to put Pro/E’s super-powered Assembly tools to work for you)

BENNY: Last month, the new Spiderman 3 movie smashed box office records, leaving fans marveling at the speed and power of the superhero’s special tools. That got us thinking about how the good people at Parametric Technology Corporation have also built some pretty powerful tools into Pro/E. Right Bruce?

BRUCE: That’s right, Benny. They may not be as exciting as Spiderman’s web-shooters, but whether a design is simple or complex, Pro/E offers a number of Assembly tools that can conquer any task with amazing speed and efficiency no matter how many times a design is modified.

BENNY: The Assembly tools we’re going to highlight are faster than a speeding bullet, more powerful than a locomotive, able to leap tall buildings in a single … oh, wait … wrong superhero.

BRUCE: That’s okay, Benny. With all the excitement, it’s easy to see how you might get confused. But there’s no doubt: Pro/E’s Assembly tools make short-order work out of what could otherwise be a tedious, time-consuming task that could break the will of any superhero.
So, let’s get started.

How would you describe PACKAGING, Benny?

BENNY: Well, let’s say we have an assembly that’s made up of ten separate components, all of which need to be fitted into a specific space. Like its name implies, Packaging allows us to move each of the separate components around until we find the best fit. Then we can go back and constrain everything.

FIGURE 1: In addition to the other uses mentioned,
Family Tables can be used to create assemblies that
include different combinations of components.

BRUCE: Packaging is especially important when considering design alternatives. And when you consider the alternative, which would be to reorder components and then re-constrain, you can see how Packaging can be a real time-saver.

BENNY: What about the CUT-OUT and MERGE tools? These are two extremely powerful tools that I find many design engineers don’t realize exist.

BRUCE: Cut-Out is a tool we use frequently at RL Hudson. We design quite a few parts where one material is molded onto another — for example, rubber may be molded onto a metal stamping. With the Cut-Out tool, we can simply cut the geometry of the metal stamping out of the rubber material, so that the overmold geometry and volume are correct.

BENNY: Without the Cut-Out tool, we would have to manually recreate the metal stamping inside of the rubber part in order to cut that geometry away rather than just assembling the rubber over the metal stamping. The Cut-Out tool saves a ton of time.

BRUCE: Right. And it’s much more precise. But the real power is evident when design changes are made. If the Cut-Out tool is used, and a change is made to the design of the metal stamping, then the rubber cut-out will automatically update. If the Cut-Out tool hasn’t been used, some lucky engineer will get to spend hours recreating all of the cuts needed to produce a not-so-precise rubber mold.

BENNY: So, the engineer who uses Pro/E’s Cut-Out tool finishes the job light-years ahead of schedule, while the engineer who chooses the manual method … well, let’s just leave it at that.

BRUCE: Good idea. Bottom line, the Cut-Out tool can be a huge time saver. The Merge tool, which is opposite of Cut-Out, is equally powerful. Let’s say a tractor has previously been manufactured using multiple parts welded together. Assembling and welding those parts can be costly, whereas, designing a part that can be cast as a single unit can ultimately be much less expensive. The Merge tool can help the design engineer accomplish this task much more quickly and efficiently than if a new, single part were created from scratch.

BENNY: And even after the components have been merged, you can still add geometry, cut away, or make other changes.

BRUCE: Right. Now, let’s talk about one of my favorite secret weapons, CREATING PARTS IN ASSEMBLY MODE. This tool is great, because it allows you to create a new part while referencing existing components. It allows for more precise design, and you also get other benefits. For example, if any of the referenced components change, the part created in assembly mode will change with it. So, there are all kinds of added perks.

BENNY: Perks are good! The fact is, as design engineers, we spend more time modifying models than we do creating them the first time. So anything we can do to save time later on is worth the extra effort up front.

BRUCE: Like when we’re creating two or more assemblies where only a few dimensions change? Wouldn’t it be nice if we could create the first assembly, then copy it, change only the dimensions necessary, and have the entire project updated, including the drawings?

BENNY: You mean, like using FAMILY TABLES? Oh, yeah … that’s fun stuff!

BRUCE: Okay, then. Let’s talk about Family Tables. Most engineers think of Family Tables for single components that are similar, but just different in size and/or have some feature differences. But you can also have Family Tables of assemblies that include different combinations of components.

BENNY: One example is the oil tube connection shown in Fig 1. The assembly on the top is designed with a hose barb, while the assembly on the bottom is designed using threads and O-rings.

BRUCE: So, in this case, you have a Family Table of an assembly, and you are swapping in and out different Family Table instances of a component.

BENNY: Right. And the O-rings are either present or not. We only had to change features and components on one to create the other. And, as with some of the other tools we’ve been discussing, if something changes on the components that are common to both, by using a Family Table, when we change the component for one, the other will automatically update. Now that’s powerful stuff!

BRUCE: What about the REPEAT and REPLACE tools? These clearly belong on the utility belt of any self-respecting superhero, don’t you think?

BENNY: Absolutely. Both tools can save time and tedium, and make any design engineer look like a real champion because they can get things done in a snap!

BRUCE: The same is true with the MIRROR COMPONENT tool, which is exactly what it says. If you are designing anything where the left and right hand sides need to be identical, but opposite, you can create one side, then simply choose Mirror Component to create the other side. And again, every time changes are made to the original side, those changes are “reflected” on the opposite side.

BENNY: Hence, the term, “Mirror.”

BRUCE: Uh, right, Benny.

Well, we’re out of space, and Benny’s run down the hall to get his superhero cape, so until next time, remember: Use Pro/E’s Assembly tools and you, too, can be a superhero for your customers, completing design tasks with even greater speed and efficiency!

BENNY: Shoot us an e-mail to share your stories about how you’ve put Pro/E’s power’s to work, or if you have suggestions that we might share about how to get the most out of Pro/E’s powers. As always, you can reach us at benny&bruce@rlhudson.com. Pro/E is a fantastic program, so have fun visualizing all the possibilities for great design!

Pro/E® and Pro/ENGINEER® are registered trademarks of Parametric Technology Corporation (PTC).

Solutions 3Q07

DESIGNING ASSEMBLIES

(Or, how to put Pro/E’s super-powered Assembly tools to work for you)