Messages

4761

VB and the development of wizards / Re: RSLinx DDE/OPC

« on: June 17, 2014, 03:37:46 AM »

Hi Roboticist,

No worries about filling space here - thank you for posting the information.

Tweakie.

4762

Mach4 General Discussion / Re: Mach4 Printer Port Discussions

« on: June 16, 2014, 07:09:45 AM »

My congratulations go out to the Mach4 team and Art for his excellent work with the parallel port driver.

This engraving was my first test run using Mach4 ver.1767 with the Darwin driver and it behaved faultlessly (except for the final blended G00 X0 Y0 home move which stalled both motors but that was my fault for having my Velocity / Acceleration settings optimistically set way too high). The 4 holes and the profile cutting require a tool change and as I don’t have Auto Tool Zero set-up decided to give this part of the toolpath a miss. The actual engraving is not the finest – I used an old (retired) engraving bit mainly because I just wanted to get some confidence in the software without damaging a good engraving bit if anything went wrong during the run.
It is hard to describe the sound but the motion is just so smooth my machine sounds entirely different – the steppers make a much higher pitch whine as opposed to the hum they make when running Mach3.

Setting the spindle to respond to the M3 / M5 commands defies my understanding and seems to be just a matter of luck. Although I finally succeeded I don’t know how I did it or if I will ever be able to do it again. I still have no idea how I will be able to switch my laser on / off  from Mach4 but that will have to wait until another day.

I don’t know if it is just me or if others will encounter a similar issue but once everything has been set-up and is working OK – shutting down the PC then restarting the following day nothing works and the only cure has been to re-install Mach4 then enter all the settings again from scratch. This could just be a WinXP problem in the way it saves settings on shutdown but I need to investigate this further.

One major problem I encountered initially was that the graphics card fitted to my machine PC was not up to the task of handling Mach4 and this card had to be swapped out for a higher spec. gaming graphics card before I achieved anything like smooth motion from the steppers.

Overall I am very impressed with the performance of Mach4 but the initial setting-up is very different to Mach3 and takes quite a bit of learning (without a manual) but I am getting there slowly.

Tweakie.

4763

General Mach Discussion / Re: Engraving Spindle.

« on: June 14, 2014, 03:29:13 AM »

Hi Gary,

I think you would be able to do quite successful MILLING with a 5kW BLDC motor (although gear reduction may be necessary to reduce the speed). 

Quite obviously, a much smaller motor is required for engraving work (which is exactly what this thread relates to) although I quite like the idea of a 'combined engraving spindle and spot welder'. 

Tweakie.

4764

General Mach Discussion / Re: Engraving Spindle.

« on: June 13, 2014, 06:14:22 AM »

Hi Ozymax,

Thank you for your excellent suggestion - I will investigate the possibility of using a 'gov/esc' (I did not even know they existed for BLDC motors) but it sounds like a brilliant idea to me and would be a very easy solution to maintaining constant RPM.

Tweakie.

4765

Show"N"Tell ( What you have made with your CNC machine.) / Re: Marines Emblem 1st Carve

« on: June 13, 2014, 05:13:21 AM »

Nice work Artcarver - thanks for posting the GCode file for others to try.

Tweakie.

4766

General Mach Discussion / Engraving Spindle.

« on: June 13, 2014, 05:01:01 AM »

Just as a heads up…

Tests have shown that small brushless dc motors (BLDC), more usually used with RC models, (mainly because of their high power to weight / size ratio) can make ideal engraving spindles.
The construction of just one such spindle is detailed here; http://openbuilds.com/builds/890kv-ox-rc-spindle.411/
To facilitate BLDC motor speed control and operation from Mach3 I have now made a simple interface circuit which takes the Mach3 generated PWM signal and converts it to the necessary pulse stream for operation the motor’s ESC and this is detailed here; http://openbuilds.com/builds/software-speed-control-of-a-brushless-dc-bldc-motor-from-mach3.762/

Tweakie.

4767

Mach4 General Discussion / Re: Mach4 Printer Port Discussions

« on: June 08, 2014, 08:11:59 AM »

Hi Art,

That old plugin is going to take some bettering you know 

Incidentally, because the Digital Trigger only has a maximum duty cycle of 50% I am now experimenting with using an external processor to measure the PRF (dependant on Feed-Rate) and adjust the pulse width to increase the duty cycle to 95% (adjustable). This has enabled the plugin's use with diode lasers down to 150mW output power allbeit extremely slow feed-rate and my 40Watt tube to really attack Corian at 4500 mm/min. 

I look forward to following your progress in the new thread once you get everything up and running. 

Tweakie.

4768

Mach4 General Discussion / Re: Mach4 Printer Port Discussions

« on: June 08, 2014, 01:02:24 AM »

Wow! - Thanks Art, now I know what I will be doing this afternoon 

Tweakie.

4769

Show"N"Tell ( Your Machines) / Re: DC-K40 Laser conversion issue

« on: June 06, 2014, 01:34:41 AM »

Hi Jeff,

If you want to use the Z axis then it's the Z Axis direction pin# (Config. / Ports & Pins / Motor Outputs). GND is connected to the breakout board GND.

(please be aware that all the axis direction pins retain state (hi / low) until that particular axis is moved in the opposite direction).

Tweakie.

4770

General Mach Discussion / Re: Z Axis problem

« on: June 04, 2014, 01:47:37 AM »

Hi Bob,

I am pleased to hear that you have resolved the problem 

Tweakie.