New Material For OR?

Just machined bulkheads / centering rings and nose cone shoulder from Delrin® Acetal Resin.

It was selected due to the following properties:
Moisture resistance
Wear-resistants
Ability to hold tight tolerances
High strength and rigidity
Maintainability

On the down side, we failed to find a glue or resin that will adhere due to its slippery surface. If anyone intends to use this material, pay particular attention to bonded surfaces. For instance, we splined our centering rings in order to preclude movement.

According to the McMaster Carr spec sheet, the material density is 0.048 - 0.051 oz / cubic inch.

Where I could see this working is on av-bay sleds, bulkheads, and other places where hardware is generally used to secure the components... thrust plates could be another example. Interesting. Have photos/specs/price points?


Later!

--Coop

Coop

We learned about this material from my son's F.I.R.S.T. Robotics team, and decided to try it in my daughter's 4H project this year after studying the material's properties at McMaster Carr.

Here's a link to the McMaster Carr website:
https://www.mcmaster.com/#

Acetel in general:
https://www.mcmaster.com/#standard-plastic-rods/=yb94go

The material she used specifically:
https://www.mcmaster.com/#standard-plastic-rods/=yb9512

McMaster Carr's spec sheet:
https://www.mcmaster.com/#8574kac/=yb96oq

This material machines just about like aluminum, it will hold threads very well, and it's very strong.

I'll post some pictures of the build and link it here as soon as I can.

united states plastic also has acetal listed https://www.usplastic.com/catalog/default.aspx?catid=439&parentcatid=795
Rex

Rex R said:

united states plastic also has acetal listed https://www.usplastic.com/catalog/default.aspx?catid=439&parentcatid=795
Rex

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WOW! I thought McMaster Carr was high this place is $11.00 a foot higher per foot for 3 inch! However I found this place:
https://www.eplastics.com/
They have 3 inch rod for $29.08 / ft., or $12 less than McMastrer Carr. I'm saving the link to this place.

Although the materials sold by USP (and others) and McMaster Carr have very similar specs, it appears that Delrin is the DuPont name going back to the 1956 patent. I did a quick search on Acetron but couldn't find the manufacturer. So I have to assume it's another name that was derived as to not infringe on Dupont.

The polymer is Acetal Resin. Various manufactures have different brand names of it: Delrin(R), Acetron(R), etc. but it's all essentially the same stuff.

It is usually used to make gears and other plastic parts. It is pretty non-stick so many adhesives won't adhere well to it. Check with the polymer manufacturer and the adhesive manufacturer for the proper adhesives to bond the acetal to whatever you are planning to use.

Bob

bobkrech said:

The polymer is Acetal Resin. Various manufactures have different brand names of it: Delrin(R), Acetron(R), etc. but it's all essentially the same stuff.

It is usually used to make gears and other plastic parts. It is pretty non-stick so many adhesives won't adhere well to it. Check with the polymer manufacturer and the adhesive manufacturer for the proper adhesives to bond the acetal to whatever you are planning to use.

Bob

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lol, Mentioned that in the OP. We didn't have anything on hand that would stick. Tried a dozen or so glues and resins. With time running short we opted to cut splines and used JB Weld. The bulkheads may not be stuck to the epoxy, but it's not going anywhere either.

Cool find.


If ya dont mind me asking... which FIRST team?

blackbrandt said:

Cool find.


If ya dont mind me asking... which FIRST team?

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Tectonic Ninjas. Can't recall the team number. I'm trying to get them to drop F.I.R.S.T. and go with TARC.

Nice. I'm on Team 900 (Zebracorns). We got to Worlds this year and ended up on the Einstein field... missed finals by 1.66 points.

blackbrandt said:

Nice. I'm on Team 900 (Zebracorns). We got to Worlds this year and ended up on the Einstein field... missed finals by 1.66 points.

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Nice. Congratulations. I know how tough it is to get to the worlds. I just wish they'd put more emphasis on engineering and on-field performance and less on costumes and cheering sections. That's what I like about TARC. Your team advances or fails on capability alone. If you're team is in the top 100 qualifiers, you're in, matching shirts or not.