Messages

7221

Mach4 General Discussion / Re: Switching to Mach4 hobby from chilipeppr

« on: January 20, 2017, 02:12:01 PM »

Hi,
PATIENCE pills and/or large quantities of beer, LOL

Craig

7222

Mach4 General Discussion / Re: Mach 4 Machtric 2.2kw VFD Modbus

« on: January 20, 2017, 01:30:58 AM »

Hi Zuxztah,
the manual files are empty. Sounds like you know how to programme your VFD.

If you read thru the manual you might find another function something like (my Delta VFD manual):
(3) 08H: loop detection
This command is used to detect if the communication between master device (PC or PLC) and AC
motor drive is normal. The AC motor drive will send the received message to the master device.

This function you could use to test your link. The link and the VFD will have to be present and working. You may need to
disconnect the spindle while you experiment if it would present a danger.

If you follow my suggestion there should be two registers in Mach4; spinCntrl and freq. They can be observed by opening
the Regfile Diagnostics page and expanding Modbus0 using Mach4 Diagnostic tab. If you click on a register you can also
manually edit it. As the MODBUS function are executed every 25ms or so any edits will be written to the VFD.

All that is required now are some LUA scripts to auto update the registers. If you have not already done so read chapter4 of the
'Mach4 Scripting Manual' which can be opened by clicking the 'Help Docs' button in the File Ops tab with Mach4 enabled.
I will re-read them myself and come back with some suggestions.

Craig

7223

Mach4 General Discussion / Re: Mach 4 Machtric 2.2kw VFD Modbus

« on: January 16, 2017, 06:03:08 AM »

Hi Zuxztah,

, and smooth running operation with modbus, 0-10v  dosen't seem to run as reliable as Modbus

I'm not sure about that, many users run their spindles that way without problem.

If you want to run over MODBUS I can probably sketch it out, will use the manual for my Delta VFD which I imagine will be
similar to yours.

You need to set up your VFD

02 - 00

7224

General Mach Discussion / Re: Advice Needed- retrofitting lathe to CNC

« on: January 15, 2017, 12:55:34 PM »

Hi Justin,
looks like a fairly tight installation.

How about just one rail for Z, say WE 35mm rail with it spanning the gap down the middle? Height 35mm. Probably still want two
cars, nose to tail as it were.

Craig

7225

General Mach Discussion / Re: Advice Needed- retrofitting lathe to CNC

« on: January 15, 2017, 06:35:29 AM »

Hi Justin,
having a look thru the Hiwin catalogue, I don't think the MG series is going to be up to it. The MG series has just two recirculating
ball tracks, one on each side. Dynamic load rating about 5kN. The EG series has four ball tracks and is much stiffer, the same 15mm
rail dynamic load rating about 10kN and the HG series about 12kN.

The guideways and cars I selected for my mill are equivalent to the 15mm EG series and they're fine but I'm glad I didn't choose anything
lighter. 3D printers have vey little load; a lathe has cutting forces and might as well come from a different planet! Don't be duped, rigidity
is paramount, even if you get everything else right if the ways/guides are not rigid you've wasted your money. I can understand the
height limitation. The WE 27mm rails/cars have a height of 27mm and a dynamic load of 12kN. Given their width you may get away without
having a lip to clamp it to. Additionally the extra width will help if the rails are closer together than ideal. It may also allow you to have
the ballscrew along the front of the machine without it skewing.

The 15mm EG rails/cars have a height of 24mm, but should probably have a lip to which to clamp and be as widely spaced as possible.
Would almost require that the ballscrew be centrally located.

but then...there is never any load on them except for directly at the spindle

That's wrong, once you start cutting there's PLENTY of load.

As for a spindle motor, certainly servos are good and just about mandatory if you want to do any serious threading but they're not
cheap. Given that you aren't intending to cut hard materials (yeah right, you will try..I sure have!) modest power (1-1.5kW) should
be enuf. If you want to save a few bucks then a standard 3 phase motor and VFD are pretty good. Don't buy a cheap Chinese or
Indian made one tho...hook them up to a VFD and they go bang. You could probably get a 2-3 hp American/British/German/Japanese
one second hand and mostly they tolerate being driven by a VFD. I have a little 1/2 hp 3 phase 4 pole motor, with 50Hz input rated
1475 rpm for grinding tools. I regularly push it up to 3000 rpm. The rotor is as far as I know the same as is fitted to the 2950 rpm
motor, in fact probably indentical to the 3600 rpm rotor in countries with 60 Hz. Haven't blown it up yet!

Stepper motors run out of torque real quick at speed. Most two phase steppers are likely only have 5% of rated torque at 1000rpm.
Best to consider max speed of a stepper of about 500 rpm and still have enuf torque to accelerate the cross slide. With a 5mm pitch
gives you a rapid of 2500 mm/min. Clearly you could go faster with 10 or even 20mm pitch but then run out of thrust at cutting speeds.
My steppers have 10:1 planetary gear reductions and rapids are fairly slow, 1200mm/min but the thrust at cutting speeds is huge. I probably
went a bit overboard but I sure do like it when I start hooking into a bit of 316 SS.

Post a few more pics and some measurements, I'm wondering if one or both rails could be mounted on the sides of the bed and therefor reduce
the height, I wouldn't consider dropping below 10kN dynamic, I'd have to find another way.

Craig

7226

General Mach Discussion / Re: Homing switch concerns

« on: January 15, 2017, 03:25:23 AM »

Hi Timgander,
I  was concerned about repeatability as well. In the end I used top quality roller plunger microswitches (Omron
from memory) and have achieved repeatability of about 0.03 mm which I was pretty happy with.

It is possible to use 'index homing' where the machine homes to a switch per normal but then the motor rotates until
the index signal is seen. That should in theory get you within one step. Not sure that its readily available or supported in
Mach3 but its all the rage in Mach4 if supported by the motion controller plugin which is to say most of them. The 'sim' motion
controller doesn't have it so you would need a motion controller plugin that does support it. The ESS certainly does but to view
the plugin requires communication with the device, ie you can't see and experiment without buying an ESS. I believe however that
the PMDX plugin can be viewed in absence of the device and you could experiment to your hearts content without having to buy
anything.

Craig

7227

General Mach Discussion / Re: Soft limit setup?

« on: January 15, 2017, 02:28:44 AM »

Hi,
soft limits are in machine co-ordinates, if you dont' reference to a known point then the machine has no idea where the
boundaries are.

When you are setting up soft limits and confirming/testing them make sure your DROs are displaying machine co-ordinates.

You say that you are homing to the extreme left. Your X travel then should range from 0 (left) to 30' (right).
As a confirmation, home to the extreme left and carefully manual jog to the right. The machine co-ordinates should increase,
ie positive. If so your X axis soft limits would be 0 and +30'.

Follow the same procedure with the Y axis. If it is homed with the table closest to the front of the machine, then when you manually
jog in the direction of the extent of travel the Y co-ordinate will be negative. Your soft limits would be 0 and -30. If the table
homes furtherest away from the front of the machine jogging into the travel area the Y co-ordinates would be positive
and your soft limits would be 0 and 30'.

Commonly the Z axis is homed to the top of travel. In that case all your machining will be done with negative Z machine co-ordinates.
Your soft limits would be 0 (top) and -10 (extreme lowest) say. This may seem a bit backwards but it is by far the most common setup,
if you ever have the chance to fiddle with a Hass mill, thats how they do it. When your actually machining something you will be using
work co-ordinates with zero commonly the top of the material to be machined. If you want to skim the surface you would drive Z down
50 thou say ie Z=-0.05 and machine away from there.

Craig

7228

General Mach Discussion / Re: Advice Needed- retrofitting lathe to CNC

« on: January 15, 2017, 01:14:24 AM »

Hi,
cant answer all your questions but maybe some.

Is it necessary to use linear guides at all? If the existing ways are OK and don't bind up at either end of the travel indicating
wear in the ways, you could use them, saves time and money and will probably be more accurate than mounting ball ways
if you don't have skills/resources. Ground ways are much draggier than ball ways so you would need steppers with serious
grunt to overcome the drag.

If you do use guides it is recommended that one rail, the 'reference' rail be butted up to a lip that needs to be dead straight.
Not easy to achieve unless you have access to a very good bed grinder. I used 15mm Rexroth rails without a lip, ie just
relying on the 'straightness' of the rail and it turns in 0.006mm over 200mm from straight. Happy enuf. Would like to
redo that part of my design but it would COST! Probably have to hand scrape to get it right, no mean feat without really
good (expensive) granite straight edges.

What are the existing leadscrews like? If there is appreciable backlash then you will probably need to change them.
Rolled ballscrews are widely available and are pretty good, you can pretty much rely on 0.05mm per 300mm error.
If that is sufficient accuracy for the parts you want to make all well and good. If you require better you will need
ground ballscrews, C5 is the entry level accuracy, 0.018 mm per 300mm. Even C5 ballscrews are EXPENSIVE, easily
five times that of a rolled screw. The price of more accurate C3,C1 and C0 will make you wince!

Without resorting to screw mapping the absolute accuracy over 70mm (the length of your part) is 0.012mm with the
C7 rolled screw or 0.004mm with C5's.

Looking at you pic guessing the collet is C5? You could use a motor and screw with limit switches to do it but a
pneumatic ram would be much easier assuming you have a compressor. Would require a double acting ram and a
change-over solenoid, not cheap if you have to buy new but if you buy good you'll never have to fiddle with it again.

I would like to see some more pics and measurements before I comment on where to put the Z screw. In the centre
of the bed is good for accuracy but MAN do they get covered in S...T.

Cant really tell the scale of your machine or how hard and fast you need to push it to get it to make money for you.
I got reasonably lucky and got four C5 Kouruda ground screws/ preloaded ballnut/ end bearings, 400mm travel, 5mm
pitch,20mm dia in good order for $600 plus $150 shipping off Ebay. They're great. Even with small steppers thru 10:1
gear reduction get 750kg thrust..plenty enuf to break things! I think you should be thinking about 16 or 20 mm dia
screws particularly if they have to work for a living!

Craig

7229

Mach4 General Discussion / Re: Mach 4 Machtric 2.2kw VFD Modbus

« on: January 14, 2017, 08:05:22 PM »

Hi Zuxztah,
what motion controller are you using? The one I use has features built in to control a spindle. I imagine every controller
on the market has some features to turn the spindle on and off at the least and most have a PWM output that can
be used to control the speed.

You could probably use MODBUS or similar but is more complex and maybe not necessary when getting started.

Craig

7230

Mach4 General Discussion / Re: I Need to Choose a Motion Controller

« on: January 12, 2017, 11:04:21 PM »

Hi brittf,
you're welcome of course. As I said earlier I'm a Mach4 newbie as well. I chose the ESS as much for anything as I sort
of understood how it worked from both reading and video prior to purchase.

Having now used Mach4 and started to write my own customisations and so on I realise that some of the features of
controllers/plugins which I had only vaguely understood are becoming clear. If that had been the case my decisions might
have been different. Not that I'm in any way unhappy with the ESS.

I would recommend you consider the amount of IO that each solution offers. The 57CNCdb25 and (subject to better advice)
and the PMDX-411 offer the equivalent of one 'ports' worth of IO, exactly what you would expect of Mach3 and one PP. If
you are going to buy a controller you might consider trying to get more IO for future expansion. Buying 'model X' only to
find some months down the track that you want to ditch it in favour of 'model Y' wastes money which I really REALLY hate!

If that makes sense to you then the ESS and 57E/57CNC should figure in your consideration. One thing which I recently tumbled
to was that while Mach4 allows only one motion controller active at a time it is possible to have multiple IO boards active.
I am a long way short of exhausting the three 'ports' of the ESS as yet. If I do I will probably go for a 57E as the additional
IO particularly for the built in ADC and MODBUS functionality but retain the ESS a the motion controller.

Craig