Wire EDM made upgrade parts for plastic OpenPNP machine
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TheCunningFellow
Jun 22, 2018, 1:58:35 AM6/22/18
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It has been a long time coming, but I have finally got my metal parts done for my PNP
The milled bits were done on a HAAS VMC and the features are totally spot on in size. The little islands are just snug in the profiles. The pocket for the bearing is just a slight interference fit. It is all just "right".
The interesting thing to see in the photos though is the surface finish on the outside of the parts.
That speckled look is the result of the profiles being cut on a wire EDM. Not the most sensible way to make things. but to a 10 year old child with a hammer everything looks like a nail :)
Now I have got the frame all nice and rigid I can get more stuck into the pneumatic parts and the feeders.
I think I have decided to try build my own now rather than buying Yamaha CL8x units. After SMDude pointed out the SmallSMT machine used an idea similar to my proposal it has given me confidence that it was not a totally terrible idea.
SMdude
Jun 22, 2018, 4:04:11 AM6/22/18
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Looking good!
It's not my fault!!! :D
Just remember, if you want your machine to work for you asap, spend the money on the yamaha feeders. I feel that the push feeder may take a bit of work to perfect, but by all means, give it a red hot go because if it can be made to work you can fit a lot of "feeders" on a machine for cheap.
I wonder if Smallsmt can be convinced to part with the push feeder mechanism for the right price... Sure saves reinventing the wheel.
Robotdigg might even be able to source them if they try really hard ;)
ma...@makr.zone
Jun 22, 2018, 4:46:33 AM6/22/18
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I wonder if Smallsmt can be convinced to part with the push feeder mechanism for the right price... Sure saves reinventing the wheel.
There is a catch. Not a "No-Go" but you should be aware of it.
The machine loosens and then retracts the cover tapes of all feeder lines on every pick. If you have lines that are rarely used the same cover tape section gets bent over and over again and will break eventually. I know of one user who pointed out exactly this problem with his Smallsmt machine.
To be fair the Smallsmt guy admits to this, which I find a very good sign in this market:
Also be aware that the actuator is pneumatic. A cheap and simple feeder solution should not require you to buy a compressor etc. If you need compressed air, then why not go all the way to Yamaha CL?
Having said that, an electric actuator could be more gentle and the loosening of all the cover tapes could perhaps be avoided because the feed drag would be slow enough for the cover tape to be pulled back on the go and gently enough.
See also (as has previously been pointed out):
Just make sure you don't make it one rod going through all the tape reels hubs. The reels should just roll on tangential rollers somehow, right?
Otherwise the changing will be a nightmare, even if like this guy you have perfected the process and modified the rod:
BTW: showing the change on the frontmost reel is easy, do the same with the back ones... :)
There are many reasons for a cartridge design....
_Mark
TheCunningFellow
Jun 22, 2018, 5:20:27 AM6/22/18
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replied in the thread about the feeder
TheCunningFellow
Jun 26, 2018, 1:12:52 AM6/26/18
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Slowly going about the upgrade
First photo is one of the Y axis motors.
Next is the old chin-shape Z axis and A axis removed
Then the new aluminum X bracket showing the Z rail rebates milled in with the reference edge for tightening them down against for accurate alignment
The toothed belt tensioning device (Showing a bit of surface rust on the 1/2 cylinder that pushes on the belt.
Two photos showing how the Z belt is retained
A photo of the X bracket with the rails attached with long bolts and washers poking above the rail height so the carriages can't come off the end
Finally the A axis stepper with its 2:1 reduction drive so it gets 4x the angular resolution of the hollow shaft stepper idea.
That is as far as I've gotten today before running out of time. A few more days and I should have it back together with very few plastic parts left.
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