Hi All,
> Great work Mark. Yes, as you pointed, the PCB material HAS to
> bridge the two rollers and their mating grooves. They are
> adjustable but only so close together requiring a minimum width PCB
> blank. With the cardboard taped to the bottom side of the PCB
> material, the metal roller grooves have an extra bite and the drill
> bit (if used) won't go into the bottom of the machine. The reason
> for just two small hard plastic rollers is to concentrate all the
> spring force against the knurls section at those points rather than
> spread the force out, reducing the pinching force. A carrier for
> smaller PCB materials would be useful. That's one of the reasons
> for the mat that's included with the machine. Let me know how your
> experiments work out.
How about a small modification to make a proper Y axis bed.
Using suitable guide rollers (bearings) to keep a carrier aligned and then a timing belt gear instead of the grit/knurled roller. Fit and tension two lengths of timing belt below the bed that run on the gears.
> Thanks for the Zen motor URL but I'm nit sure 8500 rpm will do
> anything other than drill. The etching requires ~ >25 Krpm. If you
> find a faster motor+1/8"collet combination, it would be a welcome
> replacement to the flexible extension.
I have ordered a replacement motor for a Dremel multi tool. They have a range (series 800 and 8000 in some locales) of Li-ion cordless tools that use 10.8V to match the 3-cell batteries. The price was so low I did not write it down but I remember it being around US$30 or so. The motor comes with the collet taper and an external shaft steady bearing. They are not high power by any measure but are rated for 30k+ RPM. I know a commercial PCB fab here in South Africa used to use the mains multi tools for PCB drilling years ago, he regularly replaced the bushes and brushes from continuous use.
They are similar in size to the small Roland engravers (MDX-15/20 I think is the model) but must be cheaper than the Roland replacement parts, US$650 for the yummy ones. The 3rd party site below has some prices and most of the Roland units have the motor and spindle belt driven.
http://www.advancedcolorsolutions.com/accessories/roland-engravers/engraver-spindlesYou can look at the exploded view of the one model on the spare parts site www.powertools-aftersalesservice.com/public/dremel and enter the following as the part number of the search, be patient, the site loads slowly (for me at least).
F 013 800 067
Any ideas on the life one could expect for a cheaply light weight spindle. I saw some 800W spindles with a real collet taper on eBay for US$80 but they are too big for a Cricut :-)
> I designed a quick ckt for use with Mach3. It uses the latest
> BigEasyStepper (2A, 35v and 16 microsteps) offered on Sparkfun.com
> to directly control the steppers and their 1A PWM motor driver for
> the solenoid.
This is the brute force method that will work, using the built in controller with new firmware should be a cleaner solution if the protocol cannot be reverse engineered.
My wife recently got a Cricut as a hand me down and while it can do what they want it is irritating to have the controller protocol locked. Two commercial fixes were closed down. There have been two private projects to make it work.
One guy reprogrammed the AVR processor to change the protocol (Freecut). The readme file is on the github landing page.
https://github.com/Arlet/FreecutThe other is a Linux (libcutter) driver from what I could make out, seems like it is working to some extent.
http://built-to-spec.com/cricutwikiThere is an interesting dissection as well.
http://www.built-to-spec.com/blog/2010/02/27/cricut-personal-dissection/ Then there is a long thread on the RepRap forum.
http://forums.reprap.org/read.php?128,1496Be interesting is any on this list have the time to check. My wife will not let me experiment on her cutter unless I can confirm that it will work on her Mac when I am done.
Kalle
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Johannesburg, South Africa