Plastics Design Tools: Indent

Indent is one of those tools which if you don’t know what it’s for, you might not be inclined to use it. It’s not even on any CommandManager toolbar by default. But let me tell you about one project I had where it absolutely saved my bacon.

This was some sort of a point-of-sale cooler that you might find in a convenience store for putting ice in it, and then cold drinks inside. There were multiple parts, and I was having some difficulty with the red part shown here. It was one of those parts where you could probably use the Shell feature twice – once on the inside and once on the outside. Lots of long draws in the mold, and lots of single-thickness plastic.

Anyway, I had the project mostly done, and as any design contractor knows, once you get past 80% on a job, the customer is most likely to come back at you with a change. This was just one of those parts that I didn’t really want to change because it was not only going to be a lot of time to go into the change, but also a lot of time going into all of the fixing the errors that the change caused.

I’m not usually the kind of guy to just cut out part of an existing model and model over that area, but in this case I was working with an imported part, and there was no history to go back and repair. Rebuilding this with features was probably going to add 10 hours to the project, but being smart about it would add maybe 30 minutes. So in this case, I went for the fast fix.

The image here shows the original and changed parts, with the changed parts in yellow. Going back in the history tree on parts like this can be painful. It wasn’t that complicated, but there were just a lot of things dependent on one another.

This image is shown in section view. This is the first area where I made an Indent feature in this part. I had to add a groove to this handle. That in itself isn’t a huge task, but when you realize you have to not only make the groove, but also put in a wall thickness for it under the handle, it just leaves you looking for another method.

So, I added a new solid body that represented the space in the groove that I wanted to create. That is represented by the blue body shown below.

Notice the wall around the blue body in the image on the right. That is the result of the Indent feature. Without Indent, this would have been a cut, then a revolve up to body or maybe a bunch of Delete Face commands. In the end, the tool body was the only thing sloppy, and that gets discarded anyway.

This is how the Indent PropertyManager works. Target body was the red part, and tool body was the blue groove. You have to pick the tool body where you want it to add material. Assign a thickness of material to add, and you’re good to go.

The second Indent I used in this part was a bit bigger and saved me a lot more time.

The new design is on the left, and the old is on the right. I had to change a big curved face to a couple of flat faces. Remember this was an imported part, so it wasn’t like I could just go back and change a big solid body before a shell feature.

This again would have been a lot of time to recreate manually with a bunch of thin walled features. It had the potential to be really ugly.

So what I did was to start with the old design, and create the new green body shown below.

This allowed me to make the new face as part of a solid. It essentially just pushed the face of the existing part in to match the green tool. It allowed me to match the part thickness and everything.

You just can’t beat what a great job the Indent tool did on this plastic part.

I’ve found you can also use this to simplify the creation of screw mounting bosses in curved surfaces of plastic parts. The parts don’t even have to be plastic. Castings and really anything that has a constant wall thickness.

I would probably avoid using this on sheet metal parts, as the Forming Tool does something similar but specially tailored to sheet metal parts.

Anyway, I just wanted to show a real life example where the Indent tool saved me a lot of time. I’m sure you can come up with some examples where you wished you would have used it.