Protecting the Pods During Cuts
Some point-to-point equipment leaves hold-down pods exposed to damage during cutting. Here are ideas for minimizing the problem. February 8, 2008
Question
Our company has an older - err, ancient - SCMI TECH 100 point to point. It's a good machine for what we need, and it's been maintained well. It has a pod and rail system, and it has been our company's practice to always cut 2mm shy of the material thickness if nesting curved parts or whatever, then taking it off, and hand routing it with a flush trim bit to separate the pieces. This is very time consuming, and I wonder if there's a better way. The truth is, it's been our policy to not go through the material at all, not on pieces that are cut on the beam saw, then brought over for a route, nor any holes. (Any holes that need to go through are drilled by hand after the machine.) I'm wondering how you avoid excessive damage to your pods and rails, while cutting or boring all the way through.
Forum Responses
(CNC Forum)
From contributor D:
I understand that pods can be expensive to replace, but on the other hand, labor to route and drill through a part is not cheap either. The method we used to use was to place pod locations on the label of the part to machine. This did not eliminate all of our problems but did cut back on the pod replacements. Ultimately it is up to the operator to place the pods correctly. You would have to look at the cost of replacement pods versus the extra labor. I eventually started to make some of the replacement pod parts on the machine for a fraction of the cost from the manufacturer.
In the end we found the cure for pods. The next machine had a flat table with a spoil board (no pods). Instead of replacing pods at $100 plus, we now resurface and when needed, replace the MDF spoil board when required. Cost and setup time (no time to locate pods) is greatly reduced.
From contributor J:
Our CNC is pod and rail and we through-bore and route shapes and angles all the time. We simply place the pods where the tools miss the pods. Am I missing something?
From the original questioner:
On our bed, the top of the rail is flush with the top of the pods, which makes it a lot less user friendly to cut through. Now we do have spacers that go on the pods. Maybe I should look more into them, or replacement pods that are taller. By the way, where are you getting your replacement pods?
From contributor M:
Use your spacers. They will get cut into, but you can make more. You can also make them any shape or size that you may need. Just because it's a pod and rail machine doesn't mean that you can't use a spoilboard. Basically that is all your spacers are. I have a Morbidelli U550 that we bore through, rout shapes. Whatever needs done, we try to do it all, so that when it comes off the machine, the only thing it may need is sanded.
From contributor B:
What do you mean by "spacer"? Is it a piece of material about the same shape and size as the pod, with a hole in the bottom and a gasket on the top? A "pod on top of a pod"? If that's the case, it seems like a great idea!
From contributor L:
I run a Rover 321 and the pods are at the same height as work table strip. I cut, route and drill through the material every day. The trick is to set the depth of the cut of the router bit .20-.50 thicker - 19.3 material, 19.85 cut. I rarely cut through the pod gaskets and yes, we do score through the work strips, but they are not only re-surfacable, but also replaceable. I onion skin very rarely, because it costs so much on the bench - a good operator should be able to locate the pods at the right place and save the pods and a load of work.
From contributor S:
We onion skin only when the parts are really small. Other times we put a piece of lightweight MDF over the pods and suck through that. Cheap and easy. You can also onion skin on top of the MDF for smaller pieces and make a final cut to release the part. This method is helpful when the parts are small compared to the cutting forces needed to cut them out.
From contributor M:
Yes, my "spacers" are square pieces approximately 6"x6"x3/8" thick that I place on top of the pods and rails. I have a hole drilled into them so the vacuum will flow through from the pod. I have a gasket material applied on the top side to seal the part to the spacer. I then move them (pods with spacers) under the part where they won't get machined into. I then can cut all the way through without machining into the pods or rails, thus saving me money. The only thing I have to keep in mind is that when I design an edge profile cutter, they cannot hang below the bottom side of the part by more than 1/4".
