Messages

7491

General Mach Discussion / Re: what computer for Mach3 - is "all in one" OK - is a parallel port mandatory?

« on: December 18, 2015, 05:36:37 PM »

Hi there,
Mach3 requires very modest computing power, a single core 1GHz CPU will do the trick. In the days when everyone used parallel ports what was more
important was that the 'pulse engine' that handles timing runs undisturbed by other processes/threads running on the computer including graphics.
More recently with the advent of external motion controllers the ability of any given computer sucsessfully running Mach3 has increased dramatically.
As for the 32/64 bit question I have yet to see anyone claim that Mach3 benefits from 64 bit, aside of course not being able to run PP. It maybe that
graphics are improved with 64 bit and therefore not steal resources off Mach3 for a more reliable run but have not seen any evidence of it.
More recent versions of Windows have increasing levels of security code, internet, anti-virus, firewall and Ethernet checking. All have application in
a 'connected' PC which is our norm these days but a machine controller is best/ most reliable when not connected at all. All that extra security code
becomes an impediment rather than a help. My suggestion is that you don't 'connect' and do away with all the security junk.

Craig

7492

General Mach Discussion / Re: Losing Zero

« on: November 30, 2015, 05:26:01 AM »

Hi Russ, I think Stewarts suggestion is very good. I rather think the manufacturer would be reluctant to release a machine that did not
perform as advertised given that the controller is Mach3 and any problems will be aired on the forum, the very same customers the
manufacturer is trying to attract.
There are articles on the net about stepper torque and microstepping, I have lost the links tho. The upshot is that deep microstepping
causes torque to decrease even worse than running them at speed.
May I suggest that you disable microstepping, most likely switches or jumpers on your drives, and rerun your test. Given that the z axis seems to be
the problem child just the z axis will do. The articles I have read suggest that half stepping actually improves torque, 120% of full step torque. Set your
drives to half step.
It may well mean your resolution is less than you would like but probably a good experiment which may help you to  home in on the fault without
having to spend anything or pull things to bits.

Craig

7493

General Mach Discussion / Re: Z-Axis Repeatability: Small Changes

« on: November 29, 2015, 01:30:17 AM »

Hi rrsquez,
what is the resolution of your setup ie steps per mm. What you have described sounds like the machine is driving down by say 100 steps
but only retracting 99 steps. After a number of moves the depth of cut will increase.
I cut PCB's as well using PCB-gcode plugin for EAGLE, are you doing similar? I had to do quite a bit of work to get the bed of the machine
flat with respect to the z axis and can maintain cut depths within 8um ie 0.008mm and was quite pleased to achieve that. I would have thought
cut depths of 10um ie .01mm quite a challenge, certainly not one I can match.
For most stuff I do I use a 0.4mm two flute endmill, I find the clean cut by comparison to a V bit preferable. For really fine quad flatpacks I have
to use a V bit tho. Doing this I can achieve trace spacings/widths of 0.2mm, I had hoped to get to 0.1mm but found the results not reliable enuf
to warrant populating the board.

Craig

7494

General Mach Discussion / Re: Losing Zero

« on: November 29, 2015, 12:45:14 AM »

Hi russh,
followed up and searched for your machine and it lists servos as an option, microstepping stepper motor as standard.
I imagine you would know if you had paid extra for servos.

Craig

7495

General Mach Discussion / Re: Losing Zero

« on: November 29, 2015, 12:33:28 AM »

Hi russh,
watched the vid and I'm jealous! Looks the business. I noted that the note that introduced the clip said 2200 W BLDC spindle and
SERVO control. Is that how your machine is fitted out?
Might be worth an email to the manufacturer to clarify what 'servos' were actually demonstrated in the vid and if your machine is the same
spec.

Craig

7496

General Mach Discussion / Re: Steppers and machine sounds bad, but not when rotating the toolpath

« on: November 28, 2015, 05:10:05 PM »

Hi andythepandy93,
I can only think of one explanation of the problem you report. The odd/poor sounding of the steppers must come from losing steps or
velocity/accelerations set higher than the steppers can physically handle, maybe heavy load on the table or similar.
When you rotate the axes now both steppers are operating and the load is shared between them. If you rotated by 45 degrees they would
share equally. Ten steps in X and ten steps in Y results in 14.4 'steps' along the new axis...
Could you try an axis rotation of 90 degrees so effectively x becomes y and y becomes x. If my theory about load sharing is correct then
your reported problem should recur. Would give some proof without to much shagging around.

Craig

7497

General Mach Discussion / Re: Losing Zero

« on: November 28, 2015, 04:47:41 PM »

Hi russh,
sounds like the weight of the z axis will be a challenge. Maybe you could consider a gear reducer, they really improve torque/thrust.
Most of my toolpaths are 2d in the sense that the z axis lowers to to fresh cut of say 2mm and then x-y take over until a fresh cut is to be made.
If my z axis is slow it doesn't matter to much.
Low backlash planetaries are not cheap even second hand but are available for most steppers are pretty easy to fit. The ones I use are 23 size
so a 23 stepper screws directly to the input and the output mounting is 23 size as well so you just stick it in between as it were.
The only time the reduced axis speed is really going to hurt is when you do co-ordinated moves like helical cutting or 3d contouring. Even then you
are likely to be at federate which is so much slower anyway.
I amongst other things engrave circuit boards and particularly when drilling all those little holes with tons of small z moves do I miss fast rapids.

Craig

7498

General Mach Discussion / Re: Losing Zero

« on: November 28, 2015, 03:37:19 PM »

Hi russh,
what is the pitch of your lead screws? I use 5 phase Vexta steppers, I wanted the better resolution (500 step per rev verses 200 step per rev for more
common 2 phase steppers) and smoothness at full step. When researching I found the Vexta website handy because they have a graph of motor torque
vs speed. As it turns out a motor rated at say 200 oz.in typically measured at around 100 rpm is likely to be only 20 oz.in at 1000 rpm.
More research has shown that all steppers are broadly similar in that the torque diminishes rapidly at speed. Microstepping makes it worse.
The bottom line is that stepper motors have no grunt at speed, and you will lose steps or stall if you try.
My steppers are fitted with 10:1 low backlash planetary gear reducers, with the reduction even modest steppers produce great torque but very slow. My 'rapids'
I have settled at 600 mm/min with 5mm pitch screws ie the screws at 120 rpm and the steppers therefore at 1200 rpm. When tuning/experimenting I tried a lot faster,
one stage I had rapids of 2100 mm/min ie screws at 420 rpm at steppers at 4200rpm. They ran hot and very unreliably.
As I progressed I found that at 600 mm/min I could back the drivers off a wee bit and still have reliable operation even with 30 kg on the table. At cutting speeds
around 150 mm/min in steel I have 80kgf of thrust so plenty of grunt...
My advice is don't try to run steppers fast, they don't like it and you will break tools like they're going out of fashion.

Craig

7499

General Mach Discussion / Re: new computer can't jog faster than 50 ipm?

« on: November 28, 2015, 02:40:24 PM »

Hi Fastest,
I haven't tried a touchscreen so can't say definitively. Certainly the OS has the necessary software to recognise a touchscreen and others use
them so I believe that it would work.
I have found that my budget does not run to such things. If I had several hundred to spare I would uprate my 23 size steppers with planetaries to
grunty 34 size steppers without gear reducers or finish my high torque spindle for spinning face mills or finish my 4th axis drive or buy a direct
drive servo for fifth axis or... and so the list goes.
The main advantage of Mach3/Mach4 is that it is useable software for readily available and cheap computing platforms at a very good price. I accept the
limitations of Mach3 including the PP as the best I can afford. A Seimens 328D controller is on my list but way down there.

Craig

7500

General Mach Discussion / Re: new computer can't jog faster than 50 ipm?

« on: November 28, 2015, 03:38:15 AM »

Hi Fastest1,
the board I use is a UNIGENS UMB1 which is a MiniITX dual core Atom running at 1.8GHz. The graphics unit (GPU) is built in and shares main RAM.
The NM10 chipset includes a PP. So yes the graphics and PP are effectively included. My board is fitted with 4 Gig of RAM but in fact I wasted money
there, 2 Gig would have been ample and a 64 Gig SSHD. It has one PCI slot which I use for a second PP.
The wee Atom is not a powerful computer by any stretch but has run perfectly from day one. I have seen people spend big bucks on powerful platforms
only to find they don't work as well as an old XP from the ark.
I believe the real reason that this platform works as well as it does is the OS. As I mentioned I installed Windows 7 Embedded. Embedded OS's have been around
a long while, there are a few flavours of XP Embedded for instance. They are typically used by manufacturers for specific or otherwise dedicated devices, Point-Of-Sale
machines as an example. Windows 7 Embedded (Standard) has a very user friendly setup and installation suite which is why I chose it. XP Embedded has 15000 software
modules to chose from when installing, I am no expert and that looked daunting to me.
When you install an embedded OS you can chose certain modules that you want and deselect those that you don't. For my purposes I elected to do away with the modules
associated with Internet and Ethernet security. Those processes have to run in the background continuously and interfere with what you want to run. I don't wish to
expose my machine to the Internet nor put it on any network, I want it to cut chips and nothing else.
If you search for 'single board computer' or 'miniITX' you will be flooded with hits....
MiniITX.com has some very useful combinations that would suit a Mach3 controller for under $100 US.
If you use your existing power supply and monitor and if you have a SATA HD you are there....

Craig