Help with the basics (Plastic routing)

[craigdlm]

Hi guys, I'm 'new' to routing. I've previously worked with metalworking manual mills and CNCs, injection mould tooling workshop. Our company has just invested in a RoutOut CNC router (wood/plastic) and I was wondering how people zero'd/found the centre of plates etc. Is it just using the wobblers (some call wibblers)? I used to use those and also a clock with a ballnose needle on the front but as the work isn't so thousandth of a mill as with metalwork, do I need it or will the wobblers do?

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[awerby]

I'd think the edge-finder (wobbler) should be sufficient. Find the edge (I usually feel for it,without running the spindle, rather than try to see it). Set that as a temporary zero point, then measure the width of the workpiece, divide that by two and add the radius of the wobbler. Go to that coordinate and reset the zero there. That should get you pretty close to the center.

[mactec54]

craigdlm

It's not a good idea to use an edge finder (wobbler) in a router, unless you can get it down to 800 rpm to a 1000 rpm, You can kind of guess what will happen to the edge finder at high RPM, there is a laser that is quite good

Welcome to Laser Center/Edge Finder

[craigdlm]

Fresh morning and I've just remembered the clock was used to make sure the work piece was straight (would run down the edge and the clock would show how much the part would needed to be moved to be straight/square).

So I suppose the question is, how would I do that as well. I can't remember the RPM range on our spindle. Would that laser connect up to mach3 or is it just visual.

[mactec54]

So I suppose the question is, how would I do that as well. I can't remember the RPM range on our spindle. Would that laser connect up to mach3 or is it just visual.

What ever the RPM of the router spindle is, it will not run slow enough to use a edge finder

The laser is visual, you can't use Mach3 for electronic edge finding, when your part is Plastic, you would have to have a metal block against the plastic edge for electronic edge finding to work

[coherent]

There are a number of ways to do what you are asking, but an edge finder like you may have used when working with metal, normally don't work with wood. If you are doing a number of same pieces/cuts, one of the simplest ways is to zero your table (normally via the driver software) at the beginning of each process, and fixture your workpiece (wood sheet, plastic etc) so the machine starts at the same place each time and your work is located at the same place each time. Other options that many use that work well especially for one off's, is to simply mark the zero/starting point on your work (be it the center or corner etc), then move the cutter to that position and zero your x/y set your z height then run the code. Some just eyeball it using the cutter they plan to use, and others use a small pointed bit or even a laser pointer on their Z/spindle and just jog it to the zero/start point on the material , zero the x/y at that point and run it. It mostly depends on if you need to do a lot of repetitive production work (where repeated a fixturing jig/mount would speed things up) or just a part or two then on to something else. It just depends on your needs. As a simple example, if you can home your machine to the same point before every piece, design your tool paths to always start from the center or corner of your table, and always mount your workpiece centered or at the corner on the table (or wherever), you should be able to quickly repeat or set up any work or cut without too many hassles. Your start point accuracy requirements are not the huge deal like they are when machining on a mill. As long as your start point is close and the material/table size allows the piece to cut, it's going to be correct. High precision of your start point etc may be a factor when cutting a 19.21 inch long part out of a piece of 19.22 inch long piece plastic or wood, but if you're using a 20 inch piece, no worries! Nesting your parts via your cad/cam software and cutting them from a single sheet will fix your material waste issues.
If this is some basic stuff you already knew, I apologize, but based on your question I hope it helps.