eBay cnc machines

Anything non-technical you want to talk about, talk it over and have beer ...

eBay cnc machines

Postby chicago_mike » 19 Jul 2015, 16:50

Anybody has used one of those eBay cmc machines?

http://www.ebay.com/itm/New-CNC-Router- ... 2ed6d8b36b

Been thinking of getting one of these. Also that pcbs mask paint that eBay sells. They have various colors. Blue purple and white would be cool.

Or am I just asking for trouble? :twisted:
Skyline FX 2013
User avatar
chicago_mike
Opamp Operator
 
Posts: 1711
Joined: 03 Jul 2008, 05:38
Has thanked: 23 times
Have thanks: 275 times

Re: eBay cnc machines

Postby Ice-9 » 19 Jul 2015, 18:03

In that link it looks like that model uses a parallel port which you don't find on many new computers anymore. a usb version would be better, I am not sure if a parallel to usb converter will work with this :(

I still use an old laptop with my labtool48 programmer as it needs a parallel port to work. That is the only reason I keep the old win98 laptop. It is something worth looking into if you can get it to work on usb or buy a usb cnc.
It's fairly straight forward, if you want to start it , press start. You can work out the rest of the controls for yourself !

No silicon heaven ? preposterous ! Where would all the calculators go ?
User avatar
Ice-9
Transistor Tuner
 
Posts: 1005
Joined: 31 Mar 2009, 16:29
Has thanked: 131 times
Have thanks: 338 times

Re: eBay cnc machines

Postby chicago_mike » 19 Jul 2015, 18:19

I found a few usb controllers that are pic/atmel based and they claim to work. A regular usb to parallel cable won't do it.

If the machine itself is cool, I might pick one up. I visited a board house close to me and was inspired to really do my own stuff full on. :horsey: :slap:
Skyline FX 2013
User avatar
chicago_mike
Opamp Operator
 
Posts: 1711
Joined: 03 Jul 2008, 05:38
Has thanked: 23 times
Have thanks: 275 times

Re: eBay cnc machines

Postby R.G. » 21 Jul 2015, 15:17

I have one. They work.

Be prepared to do some serious work on getting things set up straight, rectilinear and level if you're trying to hold tight tolerances on XY positions, repeatability, and accuracy. Go read about accuracy in machining; the UK "model engineering" literature from the 50s through the 70s is particularly good for this kind of thing.

They do want a parallel port. A USB to parallel is not a good solution. The way these machines get good accuracy is to do lots of real time computing in the PC and output step instructions to the XYZ motor drivers at critically important times. USB as a signalling protocol has built in delays and response times that degrade this. Worse yet, USB latency issues are not constant, which would mean they could be adjusted out. They are erratic, so USB to parallel adapters result in erratic missed steps and not-quite-repeatable positioning. A native parallel port is really the best solution.

Some modern motherboards have a parallel port connector on the motherboard, but no connector on the output. This would be fine. So -probably- would a PCIe parallel adapter card. Both solutions get mentioned in the CNC machine niche. So would an old laptop with a parallel port. This has the advantage of giving you the display and keyboard you need to drive the machine.
R.G.
Resistor Ronker
 
Posts: 339
Joined: 22 Sep 2007, 03:24
Has thanked: 0 time
Have thanks: 41 times

Re: eBay cnc machines

Postby apollomusicservice » 21 Jul 2015, 19:20

A few years ago, I made my cnc router from the control electronics to mechanical installations.
For that purpose I bought a used laptop with a parallel port and use it only for the controlling CNC.
I tried the USB / parallel interface but I find this solution more practical to have a laptop for router.
User avatar
apollomusicservice
Resistor Ronker
 
Posts: 323
Joined: 04 Jun 2012, 12:54
Has thanked: 60 times
Have thanks: 684 times

Re: eBay cnc machines

Postby chicago_mike » 21 Jul 2015, 20:18

I figure I can find a cheap ass happy to work the cnc machine.

I want to make pub's that way. :D Plus I can mill nice faceplates too.



HOPEFULLY :oops:
Skyline FX 2013
User avatar
chicago_mike
Opamp Operator
 
Posts: 1711
Joined: 03 Jul 2008, 05:38
Has thanked: 23 times
Have thanks: 275 times


Return to Freestomp Café!

Who is online

Users browsing this forum: No registered users and 5 guests

cron