[Nick110702]

Hello!
I have never posted in a forum before... fair warning. My company produces conveyor belts and I am working on a project to improve one of our processes. I am hoping someone here might have some insight to share.

We are creating what are called depanner belts. It is a sheet of fabric reinforced PVC material. It is very soft around 70 - 80 duro. Or about the same as a car tire. We use a CNC router table to machine most of the recessed holes, but then we splice ends of the material together making it endless. We then have to finish the missing holes in the splice area by hand and this is where we struggle.

Currently trying a plunge router with a 1.125" 2 flute bit (pictured). See pics for inconsistent results. We get a lot of flashing and inconsistent depths as the bit warms. Keeping the bit cool is tough when you have a few thousand of these recesses to make every week. It feels like we need a sharper bit that will cut/peel chips without melting. There are so many bits to choose from, I do not know where to start.

Any thoughts or help is very much appreciated!

 

[jw2170]

Welcome to the fourum, Nick.

 

[old55]

Welcome to the forum.

 

[DesertRatTom]

Last time I ever spliced something like this was 16 mm film. The key was having a splicer that had sprokets that aligned the film at the splice mark. Once registered, you cut a small overlap and applied cement. But it's the registration that allowed you to cut quickly and precisely. I take it the belts have to be a very specific length, so registration pins BEFORE cutting length would be a starting point. Then you could use a CNC to cut the holes, or some other form of cutter. Perhaps more of a punch rather than a router or spindle as in a CNC.

The registration pins can be fairly far from the cutter, whichever method you want to use. If you were cutting 10,000 holes per day, I'd have a multi-hole punching bar made so you could do it in a single, quick operation. Labor intensive tasks, or slow methods really slow down processes and cut profits.

Did some consulting with a couple of engineers years ago, and they always did a cost benefit analysis. If they could save the cost of 2 years of labor with a specialty device, they had no problem landing a contract.

Seems to me that you have a lot of specialized knowledge, and that if they could spend some money to reduce your time spent doing this, they could have you doing other important work. Find a process engineer to come up with a solution that works (eg: how do you do an automatic cutting device on a continuous belt. Somehow, you must have a way to mount and dismount the loop.) I would definitely be looking at a CNC laser cutter. It's light weight so you'd have a lot of flexibility for mounting it with a minimum of support, so it's open on one end for the loop. Same with the table, around which the loop can slide.

The nice thing about registration pins, is that they aren't particularly difficult to make. From there, the rest is not a particularly difficult issue. But dealing with that loop is probably going to require some heavy duty steel to suspend whatever the loop has to wrap around to make the cuts. It has to be open somehow.

I'm kind of a business guy, and this got me back in my thinking cap.

Oh yes, btw, welcome to the fun.

 

[John Smith_]

welcome to the forum.
yes, this is something that we don't come across often.
I had to google "depanning belt" and I must say, doing this by hand is a daunting and very labor intensive project.
I would be thinking of having special bits made to do both procedures in one step = the hole and the countersink.
My suggestion would be to contact a couple of router bit manufacturers with a drawing of your needs for some expert, technical advice from an engineer. And even supply them with some of your belt material for their use. and also, an anti-disclosure agreement of some sort that this idea belongs to you and your company. (sort of like a proprietary tool that you developed).
Here is my very rudimentary sketch of what I'm thinking about. In woodworking, it is called a countersink bit.

 

[MEBCWD]

I agree with John about having a special bit designed for your use to do the counterbores and holes at the same time.

Also, looking at what you need to do after you splice the belt I would think it would be worth the time and money to build a special CNC with a cantilevered arm/gantry with a hinged end that can be opened to put the spliced section on the bed and close the hinged end to support the gantry while doing the holes. When that section is finished, open the hinged end and remove the belt, insert the next one, and repeat.