[AUSTINMACHINING]

So I have a part made from .5" thick HDPE that gets machined down to .2 thick. I was able to hold it with the talon jaw vise, but by the time I flipped the part to machine secondary features, the plastic was getting pretty thin and floppy. Although I could make the part, surface finish and tolerances get worse as the vibration increased. So I designed a fixture that was the negative, of the first side of the part. A deeper pocket (vacuum volume) with vertical support pins keep the part flat under vacuum. Then thread milled some NPT holes for the PVC. Now I needed a vacuum source. So I rigged my shop vac (one of the smallest ones Rigid makes I think) up to the PVC. I can't find any specs on how much vacuum it can pull, but it felt pretty good "by feel". I new this would be the risky part of not having enough hold down force. I caught one edge that lifted and broke vacuum at 110"/min and ~.15" deep with a .5" end mill. I slowed it down to 60 and everything ran great, so i made four more. I'll eventually get a dedicated blower/pump and bump the speeds up. I've found some bypass blowers (don't depend on flow through to cool the motor) that can pull 120" H20 for under $100.00. If my leak rate is low enough, I could go with a diaphragm pump. Shot some video between too changes.

https://www.youtube.com/watch?v=khni...ature=youtu.be

[HawkJET]

Very NICE! Thanks for sharing!

Nice part too!

[SCzEngrgGroup]

Very nice! A vacuum table with replaceable "inserts" is one of the many things on my ToDo list for someday.

Get a real vacuum pump, as used for automotive air conditionig system charging. They're under $200 from Harbor Freight, E-Bay, etc.. Then make a reservoir using large diameter PVC pipe fittings. You can get narrow, soft, closed-cell foam to seal around the part - put a small channel in the plate to hold the seal in place. You can also use the "spline" used on window screens - some are smooth surfaced, soft, closed-cell material. I don't think the more common ribbed type would work well. It's dirt cheap, at about $70 for 3000 feet.

Regards,
Ray L.

[LeeWay]

Looks great. Nice thinking on the jig as well.
I am installing a couple Mini- Split heat pumps in my house and invested in a Robinar pump rather than have them Pro installed just for occasion where I may need a good vacuum fixture. I have thought there may be a very real need for such a pump in the future and you just proved out the theory for me.

What size pump are you using? Mine is a 5 cfm.

[AUSTINMACHINING]

Looks great. Nice thinking on the jig as well.
I am installing a couple Mini- Split heat pumps in my house and invested in a Robinar pump rather than have them Pro installed just for occasion where I may need a good vacuum fixture. I have thought there may be a very real need for such a pump in the future and you just proved out the theory for me.

What size pump are you using? Mine is a 5 cfm.

Thanks,
I'm using a small Rigid brand shop VAC. Cant find any specs on it. I'm going to make a manometer and measure the dead headed vacuum level and work from there. For now my shop Vac is free :-). I also just found another use for my vac plate without the need for modification. My Son is about to graduate college and had to come up with a final project. He is making a solder re-flow oven from a used toaster oven. He's using an Arduino micro and some sensors/relays/fans to controller the temperature ramp cycle. His proto is done, but he wants to clean up all the wiring by making a circuit board. Turns out the Vac plate is perfect. I ran some test cuts on a single sided copper clad board using a .032" end mill and it works great !.