Show pageOld revisionsBacklinksBack to top This page is read only. You can view the source, but not change it. Ask your administrator if you think this is wrong. ====== CNC Retrofit Kit ====== {{keywords>cnc}} ===== Overview ===== Many folks who have a mill or lathe eventually want to enhance their equipment by CNC enabling. This allows the rig to be driven by a computer, instead of being hand operated. This note documents a kit which was procured from an eBay seller who is based in China. The kit included the following parts: Three stepper motors, two power supplies, a driver board, a fan and a PC parallel port cable. {{cnc:cnckit.jpg}} //eBay item listing photo// ===== What actually turned up ===== Well, the eBay item was delivered on 26 May 2008. Took a few weeks. A large package eventually arrived. Driver board, PSUs, fan and parallel port cable look to be as advertised. {{http://farm4.static.flickr.com/3011/2517590719_25b408ba0e.jpg}} {{http://farm3.static.flickr.com/2066/2518398974_ce3554354c.jpg?350}} ======= Steppers ======= The steppers are second-hand. That said, they don't look too bad - made in Japan by Vexta - part number is PK286-03A-C9. Datasheet [[http://catalog.orientalmotor.com/item/all-categories/pk-series-stepping-motors/pk268-03a?&plpver=11&origin=keyword&by=prod&filter=0#|here]] Sold in the US for $99 each [[http://catalog.orientalmotor.com/item/all-categories/pk-series-stepping-motors/pk268-03a?&plpver=11&origin=keyword&by=prod&filter=0|here]] Specified to have a holding torque of 248 oz-inch. Each motor weighs approx 2lbs 4oz. Single shaft which has two holes drilled into it. There is no 'flat' surface on the shaft. Connectors are fitted to each stepper. These are polarised and mate with the driver board. The motor has six wires, the connector is fitted to four of these, leaving two wires unconnected. So, no effort required to work out which wires on the stepper to connect to which connector on the driver board. === Driver Board === Schematic diagram of the driver board [[http://farm4.static.flickr.com/3245/2513856602_dae1bd0e6d_o.jpg|schematic]] Datasheet for the TA8435H chip that is used on the driver board [[http://www.toshiba-components.com/products/DriverLSI/MotorControl/pdfs/TA8435H.pdf|driver]] The heatsink gets pretty warm pretty quickly. This will need a LOT of forced air cooling. {{http://farm3.static.flickr.com/2293/2517447047_ee62319577_b.jpg?400}} Click images to zoom {{http://farm3.static.flickr.com/2251/2518265364_536e0fae53_b.jpg?400}} === A case for the parts === Having a bunch of parts is all very well, but the driver board and PSUs need to be enclosed. An old PC case seemed like a fine place to start. Decided to leave the PC PSU in place - this can drive fans to cool the driver board. made a mounting plate to hold off the driver board from the chassis. Mounted the 24V PSU and the 5V PSU in the case. {{http://farm3.static.flickr.com/2311/2537945057_4d594ae0a0.jpg}} === Mach3 === This is an excellent piece of CNC control software, developed by the folks at [[http://www.machsupport.com/|Artsoft]]. Simple to install on my Win2K laptop. A few tips re setup: * Use the 'DriverTest.exe' program to check that your PC is up to the job. * For initial setup, disable the 'estop' line (but be sure to get this working later) * Ensure that you have the correct step/direction pins specified * Switch to the 'Motor Tuning & Setup' screen, then use up/down arrows on keyboard to drive the motors Great CNC pendant here http://www.randyray.com/TxMicro/ {{tag>milling}} cnc/cnc.txt Last modified: 2009/11/27 17:54by 127.0.0.1