ROLLER HOLD DOWN FOR CNC ROUTER

[mtechserv]

One of my customers has a large commercial 3 axis cnc router that is used for machining thin sheets of plaastic (mostly PVC). This machine has a vacuum table, and they are currently machining one sheet at a time. They would like to machine several sheets at a time, but of course, several sheets cannot be held with the vacuum.
I've been looking into roller hold down systems that I've seen on other commercial routers. I beleive this type of device could work for them, but I do not have any hands-on experience with roller hold down systems.

Can someone with some hands on experience with this type of hold down system provide some feedback on any benefits or issues with this type of system?


Thanks
mtechserv

[Pplug]

Call Techno CNC. I saw a roller hold down system in one of their catalogs. They have always been nice to me on the phone and always returned my phone calls. They will probably put you in contact with somebody close to you that might have such a system.
http://www.technocnc.com/

[Big S]

I have been using a pressure plate and have machined up to 6 sheets of 0.6mm polypropylene sheet at a time with this. I made my own pressure plate to suit my router.

Shannon.

[mtechserv]

Thanks for the replies so far.
I did see the Techno photos of their roller hold down. I haven't called them yet. At this point, I'm looking for someone that uses a unit like this in their daily job, so they can provide feedback as to thier likes or dislikes of such a unit.



Big S,
What do you mean by pressure plate?
I beleive you're describing what we typically refer to as a pressure foot, which is an air assisted plate that goes around the spindle and pushes on the material.
Or, are you talking about something different?


Thanks
mtechserv

[Big S]

Originally Posted by mtechserv Big S, What do you mean by pressure plate? I beleive you're describing what we typically refer to as a pressure foot, which is an air assisted plate that goes around the spindle and pushes on the material. Or, are you talking about something different? Thanks mtechserv

Yes, that is similar to what I have only it uses springs to provide the pressure. I am considering converting mine to use air cylinders at some stage.

Shannon.

[mtechserv]

When routing a stack of sheets, doesn't the pressure plate just push the top sheets around?

I'm already building a combination pressure plate / vacuum base for this customer. Basically, the pressure foot was designed to prevent small internal cutouts from flying off the table. We didn't think we would be able to hold a stack of sheets in place with it.


Brian

[Big S]

Brian,

My pressure plate has a nylon foot with rounded edges, the only time it pushed the material around was when a cutout got caught under the plate. With the polyprop sheet, I had to tape the edges of the top sheet (that stuff is pretty slippery)
YMMV.

Shannon.