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### Messages - Tweakie.CNC

6631
##### General Mach Discussion / Re: Z limit Switch with a touch pad
« on: March 27, 2011, 04:33:33 AM »
Dave,

Don't know if it's any help to you but this is how I did it. http://www.cooperman.talktalk.net/files/17.htm

Tweakie.

6632
##### General Mach Discussion / Re: Hi Fellow CNC Enthusiasts
« on: March 27, 2011, 04:27:16 AM »
Hi Lance,

Welcome to the forum.

I wrote these notes on setting up a 4th axis some time back, don't know if it's any help.

For such purposes as cutting spur gears, machining splines or flats on round stock etc etc the position of the rotary axis is usually expressed in degrees. A GCode command such as G0 A10 will rotate the axis 10 degrees and so on. To set up the axis within Mach it is necessary to specify the â€˜Steps Perâ€™ (degree) and this is achieved by taking the steps of the stepper motor and multiplying by the micro stepping setting (if any) and then multiplying by the gear ratio then dividing the result by 360. In my case this is 200 (steps) x 8 (micro steps) x 60 (reduction ratio 60:1) / 360 (degrees) = 266.6666 steps per. Unimportant really but had I thought about this a bit more at the time I was cutting the worm gear for my rotary axis I would have made the reduction ratio 63:1, then I could have had a nice round figure for the steps per degree.

Angular mode is the most common and also the most useful way in which a rotary axis is used but there are alternativesâ€¦.

When engraving on the surface of a cylinder, for example, it is convenient to have the rotary axis set for movement in mm but as this will vary, depending on the diameter of the work, there is a trick to getting it just right. One method for finding the â€˜Steps Perâ€™ is to calculate how many steps are necessary for the axis to complete one revolution and divide this figure by pi. In my case this is 200 (steps) x 8 (micro steps) x 60 (reduction ratio 60:1) / 3.142 (pi) = 30553.787 steps per to enter in Mach. Now this figure represents a linear movement of 1mm around the circumference of a 1mm diameter cylinder. In order that this can be used for any diameter of cylinder another calculation has to be performed and that is 1 divided by the diameter of the work (1/diameter). The result of this calculation is then entered into the rotary axis scale DRO within Mach. My version of Mach did not have an A axis scale DRO (like the X,Y &Z axis have) so this had to be added using Screen4 (which can be downloaded, free of charge, from the Artsoft website â€“ For reference the A axis scale DRO is OEM Code 62 and itâ€™s associated LED is OEM Code 44).
As an example, to engrave on the surface of an 80mm diameter cylinder it is 1 / 80 = 0.0125 so 0.0125 is entered in the A axis scale DRO now a GCode command of G0 A10 will rotate the axis so that the surface of the 80mm diameter work rotates 10mm. Using this method means that simple, conventional, engraving programs and existing GCode programs can be used for engraving onto curved surfaces such as tumblers, cups etc.
Although perhaps not quite as accurate as when the axis has been set up for angular movement in the first place - entering pi / 360 or 0.00873 into the A axis scale DRO will allow the axis to then operate in degrees ie. G0 A10 will rotate the axis 10 degrees.

Tweakie.

6633
##### General Mach Discussion / Re: Step motors problem - no movement
« on: March 27, 2011, 04:22:08 AM »
Just a couple of thoughts, things you may already have tried but.....

1) Try selecting the 'Sherline 1/2 pulse mode'
2) Try changing the axis step to 'active low' in ports and pins
3) Check you are getting the full TTL level (0 to 5Volts) outputs from your parallel port pins (this is best measured on the axis direction pins only)
4) Check your parallel cable is good (continuity pins 1 to 1, 2 to 2 etc)

Tweakie.

6634
##### Show"N"Tell ( Your Machines) / Re: The Laser Project.
« on: March 26, 2011, 01:23:13 PM »
Hi Pete,

She is Lena Soderberg and her picture featured in a Playboy mag of 1972 when she was in her early twenties. The pic itself went on to be used as a standard for digital image processing and the very first .jpg compression trials. The pic in it's entirety is truly beautiful and well worth doing a Google search to find.

Thanks for the encouragement, I just keep learning as I go.

Tweakie.

6635
##### General Mach Discussion / Re: help please
« on: March 26, 2011, 03:03:33 AM »
Hi,

Tweakie.

6636
##### General Mach Discussion / Re: Ordered 3 Dugong drives for my Hurco
« on: March 25, 2011, 10:14:26 AM »
Looking forward to following the thread and seeing the pictures.

Tweakie.

6637
##### General Mach Discussion / Re: mad noise and vibrations at slow speed
« on: March 25, 2011, 09:48:11 AM »
Hi Calv,

Microstepping is the way to go

Tweakie.

6638
##### General Mach Discussion / Re: mad noise and vibrations at slow speed
« on: March 25, 2011, 02:30:06 AM »
Calv,

In an X,Y move where one axis has farther to go than the other they both start and finish at the same time - one axis moves continuously and smoothly whilst the other starts and stops in jerks. This is why I said that reducing the acceleration would smooth the jerky movement and show some improvement in the situation.
(My router stands on castors and if I have the accel. set too high the whole thing starts to rock  )

Tweakie.

6639
##### General Mach Discussion / Re: Is is possible that some motherboard does not work with Mach3
« on: March 24, 2011, 12:18:32 PM »
Quote
I did place another VFD I had on hand on the back of the Z axis rather than in the control panel

Now they're no more interference to the computer.

Looks like you have solved the problem then.

Tweakie.

6640
##### Show"N"Tell ( Your Machines) / Re: The Laser Project.
« on: March 24, 2011, 09:45:51 AM »
At last I think I have finally been able to produce a raster image without any horizontal banding. It is early days yet so I must not be too complacent but I have now made some 5 or 6 of these same images of young Lena (top part of photo only - this is a family forum  ) all different sizes and without any banding at all. Like many problems it appears that there was more than one component to this problem.

Tweakie.