Machsupport Forum
General CNC Chat => Show"N"Tell ( Your Machines) => Topic started by: magicniner on May 06, 2013, 03:24:57 PM
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This is my benchtop mill -
(http://i135.photobucket.com/albums/q158/magicniner/CNCMill_zps844360e3.jpg) (http://s135.photobucket.com/user/magicniner/media/CNCMill_zps844360e3.jpg.html)
I bought it with known stepping problems at higher motor speeds and swapped out the motor & drive to resolve the problems, the new motor & drive give me 0 - 6000 rpm adding a spare PC, monitor and peripherals got me up and running with Mach3.
Some keypad controlled surfacing cuts confirmed it would do what milling I needed.
Todays project was to fit the mysterious spare engraving spindle that came with my Gravograph pantograph engraving machine, drive it from a custom made pulley on the mill spindle and give it some sprung Z freedom whilst keeping X & Y nice & rigid.
This is what I came up with -
(http://i135.photobucket.com/albums/q158/magicniner/EngravingAttachment_zps0d10be82.jpg) (http://s135.photobucket.com/user/magicniner/media/EngravingAttachment_zps0d10be82.jpg.html)
Using a custom bracket mounted on a micrometer ball slide it allows drag and cut engraving of existing uneven and curved surfaces and gives me 0 - 28000 rpm, the ball slide now resides at end of travel held by a coil spring, with the micrometer providing pre-load adjustment on the spring.
This is a drag engraving test with a non-rotating diamond tipped engraving tool -
(http://i135.photobucket.com/albums/q158/magicniner/PICT1200_zpseea53355.jpg) (http://s135.photobucket.com/user/magicniner/media/PICT1200_zpseea53355.jpg.html)
Now I just need to make up a plate for the table that allows full use of the X/Y envelope for engraving and make an engraving vice for holding all the odd things that I get asked to engrave,
ATB,
Nick
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Nice work! Is that a dryer vent hose to protect the Z's ways?
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Thanks! the Z way protection is a toilet waste flexible connector with the push-on rubber ends removed, it's slit to fit around the column and stitched back together behind the column with ty-wraps.
Once I identified the problem I adjusted end float on the X & Y shaft end bearings and eliminated the backlash that was causing problems like the artifacts in the circles in the S&W test logo above.
- Nick
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Your on your way.
Cutting is much better than dragging for small stuff. Backlash and accurate control of depth movements
becomes very important when engraving. cutting depth and size comparison attached.
Have fun....... :)
RICH
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Rich,
That's precision beyond that which I think I might ever manage!
ATB,
Nick
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Having cut my teeth (no pun intended!) on CNC engraving it was only when I tried some conventional metal cutting that I found the limitations of the 1/5 hp motor and Inverter/VFD I'd fitted to get the mill.
Last week I scored a 1 hp Inverter/VFD on ebay for a good price, the same Siemens 420 model series as the one I'd had on the shelf for the smaller motor so I had the manual and some experience. A visit to my local motor supplier and I had all I needed.
Here's the mill sporting it's new motor,
(http://i135.photobucket.com/albums/q158/magicniner/IMG_0484_zps76d3eee9.jpg) (http://s135.photobucket.com/user/magicniner/media/IMG_0484_zps76d3eee9.jpg.html)
Actually it turned out that I had a little more than I needed - see how close the motor housing is to the column? - the Z-Axis stepper mounting plate on the top of the column had to be profiled to clear the back of the motor, one cooling fin had to be cut off the motor to clear the stepper itself and a little tin work was required on the cooling fan shroud, also to clear the stepper.
The difference is amazing, I now have to consider whether the machine is rigid enough for the cut rather than whether the motor will handle it.
This is my first (a bit rough) project, the shiny bottom door links on the furnace -
(http://i135.photobucket.com/albums/q158/magicniner/IMG_0489_zps6166624a.jpg) (http://s135.photobucket.com/user/magicniner/media/IMG_0489_zps6166624a.jpg.html)
The only really critical bit is the hole spacing which, with it being CNC cut, is predictably spot-on.
I was very pleased when the helical pocketing cut to rough the hole as it looked just like the videos with a fountain of fine ally chips, I'll need some chip guards now! :)
Regards,
- Nick