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13-04-2016 #131
Ok, but if the part is finished all round that would mean diving in to fix clamps while the finish pass is running ? Or pressing feed-hold mid-cut? Neither sound good to me personally. I'm not deliberately trying to reinvent wheels, I just do what makes sense to me at the time i need to do it. The plate is fixed with the three bolts down the centre, these go through the scrap part, the outside clamps don't really do too much.
I just can't 'see' a way to clamp the parts as they are being cut.
As for spoil board then yes, if the bed was not already damaged I would fit one, this one sacrificed itself in the name of education;)
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13-04-2016 #132
Thanks Gerry,
downloaded the macro's, seems like a better system to me.
I'll keep the ref method as it is at present and try other ways of sorting it out, the bed zero method looks useful but I can see ways it would land me in trouble sometimes ;)
I am fairly certain the issue is the variable thickness of the metal, surprised me how bad it is but it does explain why the part fails sometimes.
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13-04-2016 #133
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14-04-2016 #134
Yes but the finish cut is one continuous cut, you don't want an M00 in the middle of a continuous cut because you will not get another lead-out and lead-in so a tool mark is going to show, let alone stopping and starting the tool mid-cut will probably break it.
Fitting clamps will mean working in the short space of time while the cutter is up the other end of the job, these parts are small so time is short and this is therefore dangerous. The Z axis mount is wider than the job so all clamps have to be low-profile <=10mm high or it means using a longer stick-out on the tool which again is not good on a 2mm cutter.
These are difficult parts to make well but that does not mean they cannot be made ;)
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14-04-2016 #135
Hi Dave,
I tend to use the tab method but this does leave a small witness mark (although the parts are just for me so that's ok). For customer parts I can understand why you are trying not to.
So I think if I were to try the onion skin method I would skim the bed first then zero the end of the tool to the BED. Then MDI jog the Z axis up to 5.1mm (if the part is nominally 4.9-5.1 say) and then ZERO the DRO again.
In your CAM you would than ask for a depth of 5.0mm. This would leave exactly 0.1mm of onion skin. This method is independent of the variation of part thickness.
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14-04-2016 #136
Thanks, that sounds a very similar method to Gerry's - using his "material height" DRO. I might have a go at skimming the bed and try that out.
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14-04-2016 #137
When I use the M00 I simply extend cut into scrap section past end of cut or put in a small loop and restart on a corner with change of direction and no signs of me doing so. think about it like cutting it on your manual mill overshoot on external long straightish edge to fascilitate later clamping, pause in scrap material on overshoot, add clamps to suit which could be pre mounted to swing over and clamp and carry on.
Last edited by lucan07; 14-04-2016 at 08:01 AM.
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14-04-2016 #138
Looking at your part, there are quite a few holes to screw into a spoil board so I would have the M00 after the holes were drilled to insert some screws to clamp the piece down, then just cycle start for the profile
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14-04-2016 #139
Hi
yes there are some 3mm holes on one part and a couple of useful apertures but nothing at all on the second part, on the right in the picture, I can't add any holes either :(
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14-04-2016 #140
OK then, complete the outer profile, m00, remove waste outer profile, clamp right component leaving room for profile cut, cycle start and finish profile cut to separate parts. Easy :-)
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