Messages

191

General Mach Discussion / Work & Tool Offset Backup Location?

« on: March 26, 2014, 03:16:16 AM »

I use a copy of Mach 3 without the driver installed on my CAD/CAM system and keep the Mach 3 XML and profile XML files updated from my working system.
I don't get the Work Offsets and Tool Offsets transferred across, does anyone know where Mach 3 keeps them?
Thanks,
Nick

192

General Mach Discussion / Re: Homing & Offsets Advice Request

« on: March 25, 2014, 03:25:19 AM »

Thanks Russ.
That does help, I've put a spacer collar on my edge finder to increase it's length close to the max for normal tooling, in addition to edge finding I will use it as my gauge tool for Z touch off with it's length defined from a fixed point on the quick change toolholder taper.
My table surface is now my default Z zero with work offsets for vice and fixture heights, the maths is now simple and logical rather than confusing and mind-bending ;-) 
Regards & Thanks,
Nick

193

General Mach Discussion / Re: Homing & Offsets Advice Request

« on: March 24, 2014, 08:15:46 PM »

I've worked out through a process of trial & error that what I've done can result in -ve Z at the top of travel so I'm starting from scratch :-)

194

General Mach Discussion / Homing & Offsets Advice Request

« on: March 24, 2014, 07:59:11 AM »

Having reached the point where I have a firm enough grasp of CAD/CAM to model and process through to 3 and 4 axis G code the things I'd like to machine I found the setup and workflow habits I'd aquired with one-off parts to be less than optimal for batches of parts with several tool changes - I've been zeroing the DROs for each setup and for each machining session and tool but kept getting a sneaky suspicion there must be a better way.

Searching the forum provided several hints but without all the components in one place so the following is what I've ended up piecing together - can anyone who uses Home, Home Offsets, Work Offsets and Tool Offsets sense check this for me please?  

I'm trying to get to the point where homing gets me back on Zero for the current part/fixture/tool, is the following the best/easiest/quickest process?


 
Given that I have accurate, repeatable home switches on X, Y & Z which all home in a +ve direction I've added Offsets (Home Off) under Config - Homing/Limits to give me a zero position where I want it - currently in the table centre with plenty of Z clearance for vices, fixtures, 4th Axis etc. and some allowance for tool clearance.

I suspect that I now need to add work offsets to give the correct DRO readings for edge detected or probed part & fixture edges & faces then add other Tool Z offsets to correct for each tool I want to use.

I'm nearly there but do I first add a height offset including tool holding for my probe/edge detector then add work offsets relative to that and then add cutting tool offsets?
TIA,
Nick

195

Show"N"Tell ( Your Machines) / Re: Improving a cheap 4th axis

« on: March 21, 2014, 05:54:37 AM »

My controller hardware is once again all British and my 4th axis is running smoother and faster than it was with the Chinese board I used to get it up and running.
For this I'd like to add a quick but big Thanks! to Routout CNC for taking the time to talk to me and find an appropriate matching driver board for my vintage Routout CNC controller box,

 - Nick

196

Show"N"Tell ( Your Machines) / Re: Improving a cheap 4th axis

« on: March 21, 2014, 05:46:20 AM »

I've had a couple of questions about tuning the 4th axis so here goes -
My X and Y use similar steppers, the same settings in Mach3 and my driver boards for X, Y and A are all set the same.
X & Y Steps Per: 645 Velocity: 450 Accell 45
A Steps Per: 35.55 Velocity: 1500 Accell: 80

It will depend on how you have microstepping set on your axes but if you have the driver board for rotary set the same as X & Y then the following should provide a basic start point if you have the same or similar 4th axis:

Divide X Steps Per by 18 for A,
Multiply X Velocity by 3.3 for A
and
Use double the X Accell for A

The Steps Per figure I'm using is only tuned for accuracy over 10 rotations, tape a pointer to the body of your 4th and affix tape with a line on to the chuck to give you a datum.
Align your line with your pointer and Zero A then see how many degrees a full rotation reads, tweak your Steps Per down to increase DRO degress per revolution / up to reduce degrees per revolution.
Once you have one rotation looking good test with 2, 5, 10 and so on until you have the accuracy you want over the number of revs you want, once you are refining for more than one rev you'll be adjusting after the decimal point, at 10 revs you'll probably be adjusting 0.01 in Revs Per to fine tune
Regards,
Nick

197

G-Code, CAD, and CAM discussions / Speeds & Feeds, in CAM Packages and calculators

« on: January 26, 2014, 06:10:09 AM »

I've found that the speeds & feeds in BobCad/Cam are, to say the least, a tad on the optimistic side for all materials and had been spending time with data tables & test cuts to get optimal conditions.
Last week I tried HSM Advisor and it took two minutes to deliver very close results to those yielded by hours of mucking about, so as it promises to make me considerably more productive I bought it.
Other things I particularly like about HSM Advisor are;
It takes into account machine RPM, Hp & Torque, warning of insifficient power or excess tool flex, adjusting cut parameters accordingly
Calculations take into account depth & width of cut when calculating tool flex and required torque.
It's programming allows it to locate a named active window in the CAM package and capture or insert data directly from selected fields.

What do you guys use and what do you particularly like about it?

 - Nick

198

General Mach Discussion / Re: Z Axis loosing steps in the up direction only.

« on: January 25, 2014, 04:43:58 AM »

Ideally you'd want to isolate the fault before tearing down a system and PC, swapping steppers to alternate drivers, drivers to alternate break out board outputs and so on can allow you to identify the common component or connections present on the axis displaying faults.
Trying to solve an unidentified fault using untested parts is a recipe for an extended headache, it might just work first time though ;-)

 - Nick

199

General Mach Discussion / Re: Brushless motor as a spindle ... And controll it with mach3

« on: January 11, 2014, 12:32:53 PM »

What type of input signal does the speed controller require, PPM, PWM or just variable frequency?

200

General Mach Discussion / Re: Text out of Line - Picture included!

« on: December 21, 2013, 07:31:33 AM »

If it works in wood but not metal your cutting forces may be too great for the machine, things you could try in no particular order are -

Reducing your feed per flute.
Clearing the chips with air.
A light cutting lube intermittently sprayed on the work, WD-40 or a 20/80 mix of engine oil/paraffin.
Doing the job in multiple passes, getting just a little deeper each time rather than a single full depth cut.

Regards,
Nick