Messages

221

General Mach Discussion / Re: when running part wanders to the right cutting comes back to zero off that amoun

« on: October 23, 2013, 08:51:40 AM »

Are you using a PSU that delivers enough voltage at peak demand?
My PSU is only rated at the stepper voltage  - it's what came with the machine and is probably what's required with the control box which also came with the machine.
When I replace the controller I'll be using a higher curent and voltage PSU as the new stepper drivers I'll be using control current to the motor,
Regards,
Nick

222

Show"N"Tell ( What you have made with your CNC machine.) / Pyrography Stamp With BobCad V-Carve Feature

« on: October 23, 2013, 08:21:23 AM »

I've just finished a pyrography stamp, I decided to do this one in stainless, possibly because I love a good steep learning curve 
The text is 11mm high and 40mm wide -



In this instance for the cost of return P&P I'll mill off the date, giving the couple a pyrography stamp they can use to mark a wide range of things. 

For hobby or low volume stuff an easier to machine material such as brass will be entirely suitable but I've had enquiries from furniture manufacturers and wanted to cover all the bases with the first job.

Things I've learned -
1. Use the option to rough out with a milling cutter, this will save huge amounts of time! It'll save engraving cutters too!
2. Make your stock big enough to allow the entire periphery of the job to be roughed with a milling cutter.
3. For fine detail work post the job twice, the second time with a smaller roughing milling cutter so that after roughing with a suitable milling cutter you can repeat the process with a smaller one and leave less work still for your engraving cutters.
4. Build or buy yourself a cutter grinder for sharpening your engraving cutters, you'll save yourself a mint in the long run 

ATB,
Nick

223

Tangent Corner / Re: plasma locks steppers when turned on

« on: October 22, 2013, 08:27:04 AM »

Does the plasma cause the problem if you fire it up without the torch mounted? If so the plasma could be chucking out RF interference on the mains, have you tried running the PC & control PSU etc. on a UPS to clean the mains up?

224

G-Code, CAD, and CAM discussions / Re: BobCad/Cam 4-Axis Standard problem (V25 Build 996)

« on: October 18, 2013, 05:40:55 PM »

The paths in the thin section have a "Figure Eight" shaped distortion which is not fixed by variation of any parameters rendering the rotary function usesless for this part :-(

225

General Mach Discussion / Re: Mach3 to VFD rpm difference

« on: October 16, 2013, 10:37:16 AM »

Does your VFD have adjustment parameters to allow tuning of output speed relative to input voltage?

226

G-Code, CAD, and CAM discussions / Re: BobCad/Cam 4-Axis Standard problem (V25 Build 996)

« on: October 15, 2013, 05:21:14 AM »

Double post removed and image of paths generated using 3 Base Point settings with the job split into 3 sections along the x-axis

227

G-Code, CAD, and CAM discussions / Re: BobCad/Cam 4-Axis Standard problem (V25 Build 996)

« on: October 15, 2013, 05:20:48 AM »

A very kind chap on cnczone helped out on the issue of rotary cuts below the rotary axis.

Although the somewhat cryptic Help entry gives no hint of this it’s the Base Point which needs to be set to define an axis within the part, paths can then be generated down to this Base Point. (Base Point isn’t even a point, it’s an alternate axis for the part parallel to the defined rotary axis.)
 If your rotary axis is in X then use Y and Z to define an alternate axis parallel to the rotary axis and use this to generate paths for the problem section.

Parts with multiple sections where one axis will not suffice can be processed as several sections, each with it’s own appropriately set Base Point (It’s not a point it’s an axis).

For my S shaped part I needed 3 Base Points with the job split into 3 sections along the axis,
 
Best Regards,

Nick

228

G-Code, CAD, and CAM discussions / Re: BobCad/Cam 4-Axis Standard problem (V25 Build 996)

« on: October 13, 2013, 11:47:16 AM »

As a test I constructed a very basic single throw crank and this fails in the same way -



I'm guessing it's a fault as I've not found mention anywhere in the literature that 4-Axis Standard will not cut below the axis of rotation, it might be cheque book time again!

229

G-Code, CAD, and CAM discussions / BobCad/Cam 4-Axis Standard problem (V25 Build 996)

« on: October 13, 2013, 09:56:47 AM »

I've posted this on CNC Zone and BobCad/Cam Support Forum too in the hope of the best chance of finding someone who's encountered the problem before and might have found a solution -

I spent the best part of a day fiddling with my model assuming there was a problem with the it but then tried 3-Axis options on the problem surfaces and they all worked, potentially proving the model was OK so I started looking at the posibility that it was a software problem.
Has anyone else encountered a problem in 4- Axis Standard (and possibly found a solution) where BC works around any areas of a part below the centre line, leaving large chunks of stock untouched?
With some parts it's simply a case of using larger stock and moving the part to avoid any surfaces crossing the A-Axis centre of rotation and just making more chips. I'm currently working on something nominally S-shaped making it impossible to move both low sections above centre.

Paths generated -

I've experimented with moving the part around and verified that I can move it up or down far enough to get one or other face right. It's possible to vary the ignored areas slightly by choosing cutting around or along the A-Axis, but there are no feature settings that make any difference to the avoidance of any areas below the rotational axis.

Completed simulation -


Any help would be appreciated, even a confirmation that I need to get my cheque book out again ;-)
Regards,
Nick

230

General Mach Discussion / Re: MPGs . . . Questions, Questions

« on: October 09, 2013, 06:22:01 AM »

Hood,
I plan to stick with parallel port to keep things simple and ensure continued compatibility when changing controllers etc.

I have a good tested spare parallel port card in my planned CNC upgrade PC. The idea is to install everything and configure most things offline then swap to a completely new box and have the option to go straight back to something working if I mess it up but need to use the CNC mill.

I'm struggling to find a UK supplier for encoder wheels so I've ordered one from China, (I'm guessing one could be built using a suitable pair of optical sensors and a chopper wheel - like the old style computer mice that were billed as "optical" but still used a ball & rollers with a chopper wheel on the roller shaft) I've Googled and found loads of US suppliers but not a currently trading/stocking UK supplier :-(

 - Nick