Messages

681

General Mach Discussion / Re: A axis as extruder

« on: August 05, 2013, 11:26:39 AM »

Actually it wasn't Slic3r but Skeinforge I was thinking of - see this website http://cnc2printer3d.wordpress.com/the-concept/  

682

General Mach Discussion / Re: A axis as extruder

« on: August 05, 2013, 02:43:16 AM »

There's a thread somewhere here on using Mach to drive a 3d printer.  I think either slic3r or skeinforge are used as plugins.  I hope so anyway as I am fitting an extruder to my mill!

683

General Mach Discussion / Re: Mach3 Output For DC Motor Control

« on: August 04, 2013, 05:40:15 PM »

Both of those.  And if you want to be independent of Mach for the odd hole then a standard motor controller makes sense.  It only needs an R and a C to smooth the PWM output, and maybe an op amp.  I use a KB motor controller and they are excellent ( though haven't got Mach controlling it yet).

684

General Mach Discussion / Re: Mach3 Output For DC Motor Control

« on: August 04, 2013, 03:07:34 AM »

To answer your original question, the answer is that the PWM base frequency that Mach outputs is quite low. See section 5.5.5.2 of the config guide which mentions a value of 50 Hz.  But I am sure I have seen posts where people are using even lower, down to 20 Hz.  So smoothing the signal with an RC and applying the resulting signal to a conventional motor control makes more sense perhaps to give smooth running.  If you try the direct drive it would be interesting to know the results.

685

Mach SDK plugin questions and answers. / Re: Mach iOS Pendant, finally

« on: July 15, 2013, 09:35:30 AM »

Interesting!  One question: to avoid both having any spurious bits of software hogging processor resources, and any issues with viruses etc, my workshop computer has no network connection.  Can I just fit a WiFi dongle/card and connect the iPad "peer to peer", or would I need an access point please?

686

General Mach Discussion / Re: How to set up a touch plate and auto tool zero?

« on: June 13, 2013, 07:21:14 AM »

There are several macros around on this forum, and I have concocted my own based on one of them.  Basically you set the tool over the "height finder" which is 38.84 mm high, touch the screen button for auto tool zero, the tool lowers itself gently until it touches the finder button, then lifts up to 50.00mm above the table.

As regards the touch plate itself, rather than a plate I have made a spring-loaded touch-off button which sticks to the bed with a magnet.  The advantage of this is that if the touch isn't sensed for some reason (for example I have been known to forget to connect the probe input!) the tool doesn't crash and you get at least a chance to hit E-stop before it's too late.  I didn't produce proper drawings but could post some photos if of interest to show how it's made.

I've also made a spindle probe with an isolated concentric tip 10mm dia (well, 9.97) that I can use to probe to set up X and Y edges.  There is new code for the edge finder buttons in the offsets screen. 

These features together make setting the machine datum a breeze.

John.

687

General Mach Discussion / Re: ScrewMapping

« on: May 06, 2013, 04:59:52 PM »

That sounds like backlash to me.

688

General Mach Discussion / The ultimate pendant?

« on: April 22, 2013, 05:19:30 PM »

https://www.leapmotion.com/product

689

General Mach Discussion / Re: Zeros For Different Tools With No Home/End Switches

« on: April 11, 2013, 08:27:03 AM »

I don't think that Home switches will help you here anyway, since their position will be fixed but the control point will be at different places depending on the tool length.  I think you need to zero the axes to the workpiece (not the home position).  The way I do this is to use a probe in the spindle to pick up the edges of the workpiece to set X and Y; and a tool setter on the table to set Z for the particular tool in use. 

My tool setter is a plate at an accurately known height, which is isolated from ground so that I can connect it to the probing input.  There are several tool height setting macros around on this site including a good one from Tweaky.  This way I know the height of the tool above the table surface; and I tell my CAM what the height of the material surface is above the table; so it can calculate Z to cut the right depth.  I can also do a quick search on "Z-" using a text editor on my gcode to check that the machine isn't going to try to gouge out the table.

690

VB and the development of wizards / Re: Mach3 machine material surface ZERO script

« on: April 11, 2013, 05:38:35 AM »

Andre, frankly I have learned to ignore the axes home setting!  As far as I am concerned, zero is what I set it to be.  My convention is that zero Z is the table surface; zero X and Y are (usually) the nearest left corner of the workpiece.  This way I know that any negative value of Z in the code will crash the tool into the table!  I use G-simple usually to generate G code, and this allows you to se the top surface of the "block" (i.e. material) at a known level above the machine table.  I set the tool tip to a known height by using a setting gauge, which is a spring-loaded plate that sits 38.84 mm above the table surface.  I position the tool just above this, hit the auto tool zero button, the tool moves slowly down, touches it, retracts slightly, retouches, then lifts up to Z=50 mm.

As I understand it, Mach 3 has a set of machine coordinates  which are related to the home position, in a way that you can configure.  On my mill (Denford Novamill) home is at minimum X but maximum Y and Z.  I have configured Mach3 with the corresponding maximum feed values for soft limit purposes, but actually I never ever refer to the machine coordinates, but zero the machine so that the X Y and Z DROs are, as I said above, relative to the workpiece and table surface respectively.