Design for Manufacturing Course 3: Selection of Process and Material - DragonInnovation.com

[@mithrananita1]

Nice lecture. The Pabst Blue Ribbon in the background is a nice touch!

[@DragoninnovationInc]

+Mithran Mathew thanks so much! Only the finest here at Dragon! : )

[@nraynaud]

interesting discussion around 3D printing, I'm wondering: with EDM being so slow to make the moulds, maybe there is a window for selective laser sintering (maybe that's what you referred to), even as a roughing tool? On the general discussion about choosing a process, I have seen another video suggesting going through the processes in increasing cost : can you use bent steel wire, can you use sheet metal, etc. Which also influence the design, because nobody needs a draft on a part, it's a manufacturing artefact, I think the question is more of the type: "could my part support a draft?"

[@DragoninnovationInc]

+nraynaud1 Absolutely! I'm excited about this as a future alternative to waiting 6 - 8 weeks for tools. It also opens up possibilities for geometry that can't be EDM'd or CNC'd. The downside is tool life and often the requirement to clean up the surface to get an aesthetically acceptable finish. Some CMs, such as Harbec, are experimenting with this. With regard to the second question, this is a good process to go thru. Boothroyd-Dewhurst does a nice job creating a structured process around evaluating different fabrication options. In terms of the draft, it can lead to some beneficial aesthetics, depending on the design.

[@phil.tsao.]

Thanks for this entire DFM course, it's been extremely helpful for me as I do a lot of one-offs at work and haven't had the chance to learn too much DFM. You mentioned heat staking instead of using screws in some situations. I realize it's situation dependant, but is heat staking low cost enough to use it as an alternative to screws? Or does it only really get viable when your production numbers increase? Thanks again!

[@DragoninnovationInc]

+Philip Tsao Thanks so much, Philip! From a COGS standpoint, heat-staking is lower cost than using screws, as well as being more space efficient. The downside is that it is not easily reworkable (where with screws you can just unscrew them), and you'll need a press (this can be as simple as an arbor press with a mushroom end die to form the top of the stake). The material would need to be a thermoplastic and compatible with the heat staking process (where screws can be used in a greater variety of materials).

[@phil.tsao.]

+Dragon Innovation Thanks for the reply! In terms of assembly costs, would heat staking be a little more expensive than screws? I'm making an injection molded white polycarbonate light diffuser which needs to be assembled onto an aluminum base. The two parts don't need to come apart after assembly so I'm trying to figure out the best way to assemble the two without fasteners (fasteners could be visible and retract from the aesthetics). Heat staking was one of the options I was looking into...it also gives the benefit of creating plastic feet at the bottom of the base if the die is designed correctly. What's your opinion on glueing as an assembly process? Other methods I could use are press fits, or snap fits, but both those processes result in increases in cost to the mold or machining operations. Appreciate your input!

[@DragoninnovationInc]

+Philip Tsao PC can be cold-staked. In fact, you can work it on an anvil with a hammer, just like steel - I've done it. That said, it takes a lot of force and practically speaking you may not be able to support the diffuser well enough to withstand the press force needed to peen over the PC tabs or pins. Hot staking would then be the best choice and with the use of a die as you suggest, you will get little molded feet. Hot staking would be cheaper than screws, both in materials (no screws at several cents each, depending) and labor (the hot staking operation would be quick if all the tabs or pins are done at the same time with a fixture. There would be a fixed expense for the fixture, not sure how much, maybe a thousand US but it will vary a lot from factory to factory. The next best choice would be snaps, so it can be easily disassembled. It will add a little cost to the mold, but there will be no heat-staking fixture.

[@nomoreheroes93]

Great videos, although from a studying and taking notes point of view it would be helpful to have the summary slides shown for long enough to be copied down, e.g 30 seconds, as trying to hit pause on the video when they come up isn't the most exhilarating task.

[@DragoninnovationInc]

+nomoreheroes93 Hey there! Thanks for the feedback. The accompanying slides are also available on our blog if that might be helpful: blog.dragoninnovation.com/category/design-for-manufacturing-course/page/2/

[@memofig]

Thanks. Astounding course!

[@DragoninnovationInc]

+Guillermo Figueroa thanks so much, we appreciate that.

[@Engineerboy100]

We cant see the screen!!! we need to be able to see the examples

[@DragoninnovationInc]

Hi Clint - Sorry if unclear. The link I sent you has the video, but if you scroll down, you can access the accompanying powerpoint slides which are exactly what are shown on the monitor in the video. I hope that helps, that's the best we have at the moment.