# Machsupport Forum

## Mach Discussion => General Mach Discussion => Topic started by: khalid on May 21, 2010, 07:14:59 AM

Title: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on May 21, 2010, 07:14:59 AM
See my following thread, I have converted the Radial Drill and now tweaking the controls..
I have used Ball screw and i have backlash compensation enabled in Mach3 due to some backlash in those screws... Now I am getting 0.009mm accuracy and repeatability..

Currently I am getting problems in calibrating the Z-axes... When I using Mach3 to setup it in 'MM' metric mode..I am getting 12.344 steps/mm... This is very coarse I don't know why?

My Motor is = 200 steps
Gear Reduction 3: 1 attached to QUILL mechanism
I am using 1/2 step mode...
I don't know what is driving the quill but it is something Rack and pinion, i don't know the specification..

so the mathshould be simple...
200 x 2 x 3 x Y= 1200 x Y. (Where 'Y' is the Quill rack and pinion I don't have informations about)
but Mach3 only returning me 12.33 steps!!!!!

What should i do?
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: RICH on May 21, 2010, 07:53:47 AM
KHALID,
You could make a circular paper template of know size and tape/attach it to the shaft of the stepper. Then see how far along the circumferance it takes to move the Z a mm by jogging the stepper ( i am assuming that it's double shafted). You can get rather close on the number of steps. Then just check over a longer Z travel.  The bigger the template the more accurate.
That will give total ratio ( would include the rack and pinion ). Poor mans encoder.

IE: 6" circle  C= 6x 3.14= 18.84"        18.84/200=  0.094"  so that distance along circumferance equals one step

RICH
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: manmeran on May 21, 2010, 08:08:18 AM
Early this was my problem.
please set unit to inch and test . i sure not problem when you use inch.
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: stirling on May 21, 2010, 09:05:35 AM
We know that 1200 steps turns your pinion exactly once. So to get your 'Y' you could set your steps/per to 1200 initially and code g0 Z? where ? is some suitable integer and hence allways turns your stepper full turns. Obviously bigger ? gives you more accuracy in measurement. Measure travel and stir in a little maths to taste.

Ian
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on May 21, 2010, 09:18:09 AM
RICH:)
Thanks for informations... I will certainly drive the Pinion and see how much the quill goes down with one revolution.... I discussed with one of my friend about his drill and he said that with one revolution of drill-arm, the quill goes down about 4 inches... I will check with my drill, if this is the case then the steps may be very Coarse...

MANMARDAM...
Thank you for the information... I understand what you means to change the Units...If the unit set in 'INCH' then it may be by simple math (1200 steps/INCH).. Do you belive this will solve the problem?.. I really want to know what problem you were facing?... and How much this problem was resolved at your end?.... Please help me providing more information about your experience...
thanks

IAN:)
Thank you for the response...but if lets suppose the One turn of Pinion drive the Rack down to 5inches..then this will be coarse or fine?

TO ALL:)
I am still puzzling about Turning the UNIT from 'MM" to 'INCHES'.. How does this problem can be resolved by changing the UNIT?

Best Regards and waiting for yours response SIR.

PS:
to find the Pinion-Rack ratio or travel:
200 x 2 x 3 x Y= 12.344
Y=0.010286666666666666666666666666667  What does this means???
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: manmeran on May 21, 2010, 09:25:45 AM
i think when set unit to mm ,Calculations are done wrong.
Maybe I'm wrong :)
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on May 21, 2010, 09:29:52 AM
Manmardam.. currently what Steps/Unit you have kept for Z-axis in Mach3?.. and do you have snaps to share... Again thanks for the quick reply :)
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: manmeran on May 21, 2010, 09:30:55 AM
MANMARDAM...
I understand what you means to change the Units...If the unit set in 'INCH' then it may be by simple math (1200 steps/INCH)

i mean : change "select native unite" to INCH
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on May 21, 2010, 09:35:45 AM
Yes I clearly understood your previous post for changing the Unit to INCH in MACH3 and try recalibration....I will try that too..but logically, it will have no effect on the setup... This is because whatever steps/unit i calculated in 'MM" mode, Mach3 will simply multiply them into 25.4 to get in 'INCH' mode...

Regards and thanks for your valuable time...
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: manmeran on May 21, 2010, 09:40:33 AM
yes , this calculate is simple but ...
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: Hood on May 21, 2010, 10:31:49 AM
If your native units are set to mm calculate your steps per mm, if you are in Imperial native then calculate your steps per to inch. It does not matter if your screw or rack is imperial and you are using metric native units or vice versa, all you do is convert.
I have not read your zone thread yet and will go look now but what exactly is your problem? Is your Z not accurate with the calcs you have or is it you just dont see why it should be such a small number?
Hood
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on May 21, 2010, 10:47:02 AM
Hi Hood,
Thanks for helping me again;)... Both problems with the Z....a) 'Z' is not accurate b) The Motor runs very coarse... When I was calculating the Steps/Unit with The Dial Guage (10mm Range)..and I said the Z-axes Motor to go-down 7mm.. It goes down about 6.5mm with Jerks on the dial guage...

I have installed counterweight on the Quill and it is free to move with motor pully and i know i have no missed step..it moves like butter with 1200Oz-in Motors...

I want to run it fine and accurate.. I have tried many time to Move up and down but it goes up/down with sometime 0.5mm plus and sometime 0.6mm minus of actual moves...

I don't know whats wrong?
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: RICH on May 21, 2010, 11:23:56 AM
a) 'Z' is not accurate
Racks usually have a lot of backlash in them. I am refering to those on mills and drill presses. Counterwieght certainly helps remove some but still may not be linear / accurate over it's travel. You can probably find a "sweet spot" on it for some travel distance. On my mill there was a fine feed and that's where the stepper was attached for the Z. Some day will change it over to be ball screw driven. Using backlash compensation though works quite well.
I could be wrong, but, get  the steps per unit best you can and then see / map out the Z travel.

BTW, to get finer movement of the axis, you will need to increase the steps per unit. That best can be done via gearing and going to 10u steps instead of 1/2 stepping.
RICH
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on May 21, 2010, 11:43:02 AM
Hi RICH,
hanks for helping hands:)...I somewhere studied the higher microstep means loosing accuracy...However, I am seriously thinking of, to remove the pinion and externally drive the QUILL with Ball screw... The second option is to add worm-wheel  gear box upto 100:1 ratio!!!!..

As far as Backlash, I saw this machine was used two times after it purchase for a very short run...
Best Regards
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: Hood on May 21, 2010, 01:10:41 PM
Quite hard to tell from the pic but looks like a load of gearing in the head, presume for different feedrates, you may be able to alter the gearing to get it nearer 1:1 inside the head.

Hood
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on May 21, 2010, 10:30:58 PM
Hmm.. Excellent Hood:)... As far as I know, those gearings are for Automatic Feed and driven with Spindle Motor... If I enable it with Lever, i will no more use the Manual Feed.. It Means my Stepper will not work...However, nice idea and I didn't think on that earlier.. I will look into it and see how can i bring it to nearer to 1:1.. This will be great if i succeed...
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: stirling on May 22, 2010, 02:32:26 AM
Just to cover a couple of points FYI

to find the Pinion-Rack ratio or travel:
200 x 2 x 3 x Y= 12.344
Y=0.010286666666666666666666666666667  What does this means???
That is the pinion revs per mm. The inverse (97.213220998055735580038885294699) is mm per pinion rev - so your friend wasn't far out with his 4 inches.

...I somewhere studied the higher microstep means loosing accuracy...
Kind of but not quite. usteps though obviously finer resolution than full steps are not as accurate as full steps.Therefore they shouldn't be thpught of as making a system more accuarate. i.e. full steps may land within 5% of where they're meant to wheras usteps may land within 20% say, but this is non cumulative so it doesn't matter how many usteps you have it doesn't affect your step accuracy. For other reasons though there's no point in going above 10 usteps. Think of it as usteps give smoooooothness and gearing gives resolution, wheras alround quality gives accuracy.

Cheers

Ian
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on May 22, 2010, 05:23:59 AM
Hi Stirling Thanks.. and You are right about the Pinion movement figures.. Todays i checked by turning the Feed wheel...With One revolution (rough)  I am getting 120mm Rack movement it is almost 5inches.. and this is the reason I lost my Torque:(.. With 1200Oz-in Motor i am unable to drill a hole in Carbon steel..:(...

So installing Screw or worm-wheel will give me enough advantage to drill a hole in CS and SS material...
The same motors are installed on X/Y carriage and carries 220 lbs weight without loosing steps.. They are used in 1/2 steps mode with 5TPI lead screw and 3:1 reduction gears...

Regards
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: stirling on May 22, 2010, 08:02:35 AM
With One revolution (rough)  I am getting 120mm Rack movement it is almost 5inches.. and this is the reason I lost my Torque:(.. With 1200Oz-in Motor i am unable to drill a hole in Carbon steel..:(...
Well maybe.... but I wouldn't regard 1.6 inches per motor rev as out of order or anything like. That 1200 oz/in puppy should be unstoppable. I use 350oz/in steppers at about the same gearing as you and they'd push a bus  ;D

Cheers

Ian
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on May 22, 2010, 09:00:18 AM
Hi Ian..The Gearing for the Z-stepper Motor gives Torque:
1200 Oz-in Bipolar Mode, I am using it in Unipolar so Lets say I am getting 600Oz-in Torque straight away from the Motor..
Now , 600 x 3 =1800Oz-in torque at the Feed shaft.. So do you feel good at  this Torque for drilling hole in 30mm thick Carbon Steel Plate...
Following were my setting for Z-axis  Motors

Steps/Unit= 12.33   , Velocity=10mm/min  and Acceleration=5mm/min/min
200 steps, 1/2 step Mode, 3:1 Reduction Pully and further Rack/Pinion..

The Brand New HSS 2flute drill 7.8mm DORMER, Following were the Feed and speed
Spindle RPM= 900
Plunge feed= 41.072 mm/min
Engage feed =15.402 mm/min
Cut Feed =173 mm/min
and Rapid is used as Transfer Feed

The Motor when enabled, Can't be rotated with the help of Hand Force by forcing the big Pully... I don't know How you can Pull the bus with it?

Also, I have found that when backlash is enabled in Mach3, I can't increase my IPM!!!..If I set velocity says 200 the speed i am getting like i am getting 40.. Increasing The Velocity value in Mach3 motor tunning do not affect the speed of the system:(

Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: stirling on May 22, 2010, 04:28:42 PM
1200 Oz-in Bipolar Mode, I am using it in Unipolar so Lets say I am getting 600Oz-in Torque straight away from the Motor..
Well it doesn't really work like that. The 1200 oz/in is HOLDING torque. i.e. the torque you'd need to apply to force a stationary or "held" motor to rotate. It tells you very little about the torque it actually "develops" while rotating. Drive a "big" motor less than optimally and a "small" one optimally and the small one will win every time. As for the rest - sorry - I'm not your man - what I know about drilling carbon steel could be written on a pin head. Anyway - good luck.

Cheers

Ian
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: Hood on May 22, 2010, 06:28:20 PM
Khalid
I would say your problem is your torque is drastically reduced because of the gearing in the head, instead of increasing the torque it is the opposite way.
Your reduction in the first stage increases the torque by 3 times but then going by your steps per unit compared to motor steps the torque gets drastically reduced. From what I recall your input to the head is 1200 steps per rev and your steps per mm are 12 or there abouts so the quill will move about 100mm per input shaft rev, that is a very large amount, you really want it to only be a few mm per input shaft rev. I would imagine your axis are about 5mm per rev.
Or am I reading this all wrong?
Hood
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on May 23, 2010, 03:07:43 AM
Ian, I agree with you:) Using smaller Stepper is better comparing to bigger..This is my experience too...:)
Hood.. You are absolutly right.. The Pinion-Rack are very coarse and my whole torque increment is reduced by this rack component... I am going to install worm-wheel of 30:1 ratio or a little higher 50:1 to get maximum Torque to drill and mill CS and Stainless plates..

I am giving links of completed machine with some Failed drilling pictures.... You will see I couldn't get the drill 1mm inside carbon steel plate.. The Drill is of HSS brand new DORMER make...
http://www.cnczone.com/forums/attachment.php?attachmentid=107676&d=1274598084
http://www.cnczone.com/forums/attachment.php?attachmentid=107679&d=1274598084
http://www.cnczone.com/forums/attachment.php?attachmentid=107678&d=1274598084
http://www.cnczone.com/forums/attachment.php?attachmentid=107677&d=1274598084

Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on May 25, 2010, 10:58:27 AM
As per HOOD instruction, I checked the Auto-Feed option on the radial drill...I found three speeds setting .. 0.06mm/rev , 0.21mm/revolution and 0.1mm/revolution... I have disabled the AutoFeed gearing and used 0.06mm/revolution worm set only.. I have to make new motor mount too.. I will soon post the pictures of the setup.. Now not only i will get the resolution on the Quill but the greater torque...

In the couple of days i will show some drilling work on Actual tubesheet of the exchanger:)...  Here in my Shop the Ambeint temperature shoot 49Celcius... yaa man it is in Celcies not in Farhenhite :(..One of my controller have Heart Attack (Thermal Shutdown)..Now I am going to arrange some Cooling setup for the controller panels too;)

Thanks Hood and all the folks who solved my problems....
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: Hood on May 25, 2010, 02:03:38 PM
Glad to hear you are progressing :)
It was high 20's here a few days ago and I was welding Aluminium and I was hating it, I am a cold climate kind of person. Today its been great, probably 12 degrees C and I am much happier.  ;D

Look forward to the pics :)
Hood
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on May 28, 2010, 07:13:47 AM
Thanks Hood...I wish i could have 20 degree celcius here.. yesterday we have 53 degree celcius.. I adjusted the POT on the modular card to 2.5Amp current.. Although i have 4Amp setting for high torque but the Ambient temperature is too high.. So I am running these beefy motors with 30% of their torque curve:(...

yesterday, i made some progress.. Following are the mock-up results of tube sheet drilling for one of our exchanger..
Program used:
2-VisualMill 5
3-Mach3

The feed was calculated for
1- Dormer centre drill A-201 HSS
2- Spindle RPM: 800
3- Cut feed: 215mm/min

Total holes: 220 Ea
Time         :52Minutes

New Pictures:
http://www.cnczone.com/forums/attachment.php?attachmentid=107978&d=1275044769
http://www.cnczone.com/forums/attachment.php?attachmentid=107979&d=1275044769
http://www.cnczone.com/forums/attachment.php?attachmentid=107975&d=1275044769
http://www.cnczone.com/forums/attachment.php?attachmentid=107976&d=1275044769
http://www.cnczone.com/forums/attachment.php?attachmentid=107977&d=1275044769

Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: Hood on May 28, 2010, 08:04:35 AM
Looks great :)
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on June 04, 2010, 11:31:02 AM
Guys I am getting trouble...
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: M250cnc on June 04, 2010, 12:07:53 PM
Yes i see

You say you have backlash. How much on each axis ?

Are you using conventional or climb milling ?

Phil
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on June 04, 2010, 02:36:15 PM
Hi Phil,
I currently don't remember the backlash values and also didn't  checked the rotation direction of tool.. Will answer you tomorrow:)
Regards
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on June 05, 2010, 01:39:05 AM
hi ,

Backlashs for Axes:
1- X-axis: 0.005708 inch  =  0.145mm
Y-axis: 0.013385 inch   =  0.334mm
Z-axis: 0.0535433        =  1.36mm
Backlash speed of max%: 50%
shuttle Acceleration:0.08
Mill : climb mill

Calibrated Step/units(mm) :  calibration was taken at 290mm length with needle gauge and gauge blocks
X-axes:  6093.32125758
Y-axis :  6093.32125758
Z-axes:   15177.80388
Kernel Speed: 25000Hz

I am running the steppers in 1/2 step mode.. Do we have any problem with the steps i mentioned above?

Today i checked all the things and they found tight. With the same settings as yesterday, i just plot 100mm Diameter circle and 150mm Square. The backlash for all the Axes was enabled. The circle meets all the points and were found round within 0.01mm. The Square was perfect within the 0.01mm. and the start and end point meets exactly...

This tells me that i have no motors as well as backlash calibrations issues in no-load conditions.

PS:
The circle was drawn first with Lead pencil and i measured it. but when drawing the square the pencil stopped marking. So i install the Pen, this work perfect for Square drawing but torn the page while drawing the circle.

Any thought?
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on June 05, 2010, 04:38:47 AM
Forget to write that the SQUARE is actually rotated square (45 degree) so that both X/Y motors collectively make it. So making the square both X/Y motors engaged all the times.
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: RICH on June 05, 2010, 09:35:41 AM
KHALID,

Plotting a square and circle are good ways of checking. In fact there is an old standard for actaully machining a similar piece
with a raised hub for the circle and tapered sides out to the square for confirming machine accuracy.  Attached is a picture of my adjustable
spring loaded tracing pen which i use since it comes in handy sometimes. ( no tearing of the paper)

Just a comment on the Z backlash ( .053" ). You may find that Z will push up or pull down when machining
depending on how you have it counterweighted. There is no "locking" of the rack other than weight which may
not be a problem in softer / easier machining materials. But on harder materials it could say drop into the material
some and create a problem.

RICH
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on June 05, 2010, 10:06:01 AM
Hi RICH.. First i am thankful to you for showing us a nice tool you made..:) As i have shown you the 45 degree square and the Circle..I have perfect all the things..but today when i tested on Aluminum i found some trouble as you can see in picture..
It is the picture of  a simple 5-vane open impeller just to check the machine behaviour on the Aluminum... As you have seen in the picture, the simulation perfectly shows the same resultss of my Gcode.. I am annoyed only because i am going out of my centre.. As you have seen the picture one of the Vane just at the edge of the stock... All the dimensions are perfect..and this is very strange for me..if the motor looses steps then the Vane thickness and curvature must be different but in this case it is the same thickness.. I stopped the machine when the cutter strike the clamp.. If the part was completed then may be i had some clue why this happen?

The part dmension is 110mm, the stock used was Aluminum 121mm dia.. The pocket was done in 4-passess upto 8mm depth with  7 IPM and 800 RPM using new 8mm 2-flute HSS endMill..
Any thought?

PS:
SHOULD I SAY, THAT THE TOOL IS  GOING OUT OF CENTRE? ... A little confusing to me... Seems that  stock is offset to the Geometry in the CAM software.. But when i saw in the CAM the geometry is centred in the STOCK...... i am confused because thee impeller  machining and dimension is right after removal of the part.. It seems that i have some offset of the complete part in the stock.. Help me i am in a very perplexing situation... Anything in MACH3 that can cause this???
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on June 05, 2010, 12:26:50 PM
I am posting here the screen shot of the cncsimulator, the simulation and the actual part machined matches but it is out-of-way or it seems like that.. any suggestion.. I am attaching the gcode file too...
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on June 05, 2010, 12:35:53 PM
Here is the Simulation results and Actual - side by side... The simulator is new to me so i can't color map the depth...
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: RICH on June 05, 2010, 03:01:34 PM
khalid,
Post the Gcode file.

RICH
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on June 06, 2010, 01:26:29 AM
Here is the Gcode.
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on June 06, 2010, 02:29:42 AM
The machining/pocketing of part was carried out with TOOL rotating CCW and Table rotating CW as shown in Picture..
Flood coolant was ON with 3-High Pressure high flow jet Nozzles... for the above conditions :

I plunge the Tool using Ramping technique for the Aluminum Impeller..
Ramp ANgle= 10mm
Ramp Height= 12mm
Ramp distance= 10mm
The same ramp with 5IPM and the cutting speed was 8 IPM, using HSco 2Flute 8mm end Mill...

Again , i don't know why my Z-axis goes down in the work piece... In CAM i gave 2mm DOC/Pass for the above Aluminum part and the first Pass i measured was about 3.5mm.. there is some clearances in the Quill i think that once adjusted for the first pass and then for the next consequent passes it gives me exact DOC...

The backlash compensation was done in Mach3 and in the Circle and rotated square i am getting 0.01mm tolerances and no sign of backlash.. I afraid that this is done in no-l;oad condition... But if Mach3 compensate the backlash then the problem should not appear in actual work piece...
One other thing i want to share here, is that i installed the dial guage on the tooltip.. and gave lateral movement to the quill by hand i was getting 0.5mm flex... so total flex will be 1mm that will appear in workpiece..
This is the reason I am currently making drawings of a spindle... and will change the complete Z-axes...
Do i have to rework on my X/Y cross slides?.. These slides are boxway type and very rigid.. I feel no vibration in them.. Just to check the Tramming tomorrow...

Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on June 06, 2010, 10:18:16 AM
Following is the Header of my impeller Gcode:
G90
G70
G40
g20
g64

I enabled the G64 (CV Mode is ON)...
Should this CV mode be on when we have backlash compensation ON?...

Regards

PS:
I used Quantum a lot in past without backlash compensation On and it gave me satisfactory results.. I am using QUANTUM MACH3 Version R2.43..
I have following settings to AntiJersk compensation as can be seen in Picture attached
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: RICH on June 06, 2010, 11:31:02 AM
KHALID,
Try running this file. It mimics the pump vanes and there are a number of
Z travels and goes about cutting the profile such that moves are made to different points
on the profile. The file starts at x & y =0  and returns back to 0,0 with the Z retracted to 1" above Z=0.

Note that the feedrate is set at 40 ( LINE N100 ). Change it to INCREASING different values, say 2,4,8,10,20 and see what happens.
You may want to try it in CV and exact stop mode.

You may want to put a pointed object in the quill or use your pen and trace it out on paper.

I believe it will tell something.............

RICH
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on June 06, 2010, 11:38:58 AM
Hi RICH,Thanks for coming back and the file... I just watched your file and the code contains IJ parameters ..  so should have to change to IJ mode in Mach3.

I will defintly try it tomorrow and show you the results:)
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: RICH on June 06, 2010, 11:49:42 AM
The G91.1 in the test file  is incremental IJK mode.
I don't know what your defaults are so you may want to add the G64 on a line.

Yes the code is made up of arcs instead of your posted file which were all line segments. The arcs would give a cleaner
finish pass for the vanes.

Rich
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on June 06, 2010, 11:57:05 AM
Hmm...Thanks RICH:).. I will definetly try it tomorrow and will show whats comeup with the setup:)
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on June 07, 2010, 03:44:35 AM
Hi RICH... I modified my PEN and it is working right now:) Attached picture is the result of the Gcode you provided...
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: RICH on June 07, 2010, 10:11:51 AM
Looks good, the backlash seems to be working ok on the Z otherwise you would have dug into the paper with the pen and tracking ok in the
x & y.
What F did you run it at?
Did you try cv and exact stop?
After running the program did you bring the Z down and see if it returned to the starting point? If it ran well at say one F, just double the feedrate and
run it again since you returned  to the starting point, see if it tracks the same line and returns to the center starting point. At some F she will skip
and then you will know the max velocity you can run at. Then limit it to say 50 or 60 % of ( the 50 to 40 % reduction allows for torque required for cutting).

Then you can use a end mill to do some cutting in some scrap piece experimenting with some cut depths.

After playing around you will have some level of confidence on the F /  max velocity you should be using along with anticipated accuracy.

---------------------
Your original program had short straight line segments instead of the arcs.That can create a problem for YOU depending on the accel values
and mode you are running ( cv or exact stop ).
Let me comment that in your program you clean out the bulk of the material in the first area and then finish the first vane of the impeller , then
the others go on to profile the vanes only. Do as you wish, but, i would have cleared out all the bulk and then profiled the impellers.

Like said before, wood is different than cutting metal, so fool around to gain experince with YOUR machine.

"SPEED WILL COME UNBIDDEN ONCE ACCURACY IS ATTAINED"  ;)

RICH
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on June 07, 2010, 11:39:42 AM
Looks good, the backlash seems to be working ok on the Z otherwise you would have dug into the paper with the pen and tracking ok in the
x & y.
What F did you run it at?
Did you try cv and exact stop?

Actually i modified the PEN a little .. The pen comes with spring and on One click the point comes out and on the other click the tip get inside.. I modified it a little and it worked very fine as you have seen in the picture..

I ran the Gcode with F10 and i used CV mode On...
After running the program did you bring the Z down and see if it returned to the starting point? If it ran well at say one F, just double the feedrate and
run it again since you returned  to the starting point, see if it tracks the same line and returns to the center starting point. At some F she will skip
and then you will know the max velocity you can run at. Then limit it to say 50 or 60 % of ( the 50 to 40 % reduction allows for torque required for cutting).
Yes the Program return to its exact start point..and the Z when commanded to go to zero, it exactly went to the zero location... I imported yours Gcode into NCPlot and exported in DXF... I open the DXF in AutoCAD and measured some dimensions and compared it with the pen-tracing... I was within 0.07mm range.. Amazing:)... As it was on the Paper so measurement was not easy by Vernier calipre;)

I just tried if with F10, tomorrow i will increase the velocity and will show you some more results:)... Lets say F10 is my maximum velocity then i have to keep my rapid F5 and keep the cutting 4IPM....Am I right.. My Stepper motors are for 80Volts rating with 4.2Amp per phase..Currently i am only supplying 36Volts DC.. I have connections of 48Volts and 60Volts too.. I will try increasing the voltage...

It is now clear that My Y-axis i.e. the bottom carriage , loosing steps.. This is because it carries the load of X-axis carriage+Workpiece load+Cutting forces.. It is boxway design so having frictional forces too (although i have appled Oil too)...

Then you can use a end mill to do some cutting in some scrap piece experimenting with some cut depths.

After playing around you will have some level of confidence on the F /  max velocity you should be using along with anticipated accuracy.
I will sure do so.. I am planning to use 1mm DOC for Aluminum... My Z-axis has some play, in the impeller case the Gcode was 2mm per pass and the first pass of the impeller was 3.5mm.. That was too much for the cutter..... so i will use shallow cut in future...

---------------------

Your original program had short straight line segments instead of the arcs.That can create a problem for YOU depending on the accel values
and mode you are running ( cv or exact stop ).

Yes, today i figured out how to output the gcode in G02/G03 IJK mode.. so in future i will make my Gcode more clean.. I am also planning to Use EXACT STOP MODE for milling... I hope that for better usage of Backlash compensation i should not use CONSTANT VELOCITY MODE...

Let me comment that in your program you clean out the bulk of the material in the first area and then finish the first vane of the impeller , then
the others go on to profile the vanes only. Do as you wish, but, i would have cleared out all the bulk and then profiled the impellers.

Like said before, wood is different than cutting metal, so fool around to gain experince with YOUR machine.

"SPEED WILL COME UNBIDDEN ONCE ACCURACY IS ATTAINED"  ;)

RICH
The Gcode for the above impeller was made in ARTCAM.. and I know artcam is good for wax/wood but not for metal... I will use VisualMill for my next Gcode generation projects... I will follow your advice and will post you some good results..

Thanks for being with me and helping me:)

ONE QUESTION:
If my motors do not loose steps.. Then will the Backlash compensation will be OKAY for heavy Cuts?.. I read somewhere that Backlash compensation do not work for heavy cut.. Please enlighten me:)
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: RICH on June 07, 2010, 03:04:07 PM
You don't want to skip steps for rapid moves or during actual cutting. If through eperience on many files you find that you can rapid
at 10 IPM and nothing goes wrong, then maybe try 20. if you skip then try 12 and see what happens. I don't know if 10 is near say the limit
for your machine ( there are programs that can be used to evaluate the adequacy of the system for a given rapid ). It's more than just the velocity
as accel / decel is important also. You just want some headroom / be at a combination of velocity / accel setting that you can be confident with.
If your at the edge of settings, say your machine is not lubricated well, then addtional additional stepper torque will be required at that setting and
thus you could skip, so you reduce the settings.

Now when you start cutting metal, additional torque is required, so you know you want to be below what the confortable rapid is.
There is a big difference between Al, steel, cast iron, etc. SO maybe you find that all is well with Al but you need to adjust for the harder to machine metals.

Best point to be made to you is, the axis settings should be such that the axis can be run at with max POWER (  =SPEED x TORQUE) relative to the stepper motor curve.
Of course consider F and spindle speed ......etc when doing something.

---------------------
Carefull with the backlash, with small diameter end mills you can break them in a heart beat. Rule of thumb is max depth of cut  less than 1/2 dia of mill.
BC works fine for me for whatever i have done. The "heavy cutter" folks  can chime in with their experience on any problems.

My 50-50-50 rule which you may want to consider.
50% - The max velocity is 50% of where your steppers will start to skip
50% - Set the shuttle Wheel setting in configuration to .0050  to .050 ( .5 too slow )
50% - Backlash speed
This is a good starting point and refine upward, but always leave say 30% headroom

RICH
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on June 12, 2010, 09:00:49 AM
Hi Rich,
I have checked the Gib Tighteness... Following were my observations:

1- The Y-axis Ball screw has 3inch dia pully installed.. I removed the belt and rotated the pully with One thumb and 3-Fingers... I was feeling the force of moving the Slide... The Screw has some spring action inside.. The wheel is turned first upto a limit with the screw and then screw nut takes the load and further after quarter turn the slide was moving...

I then adjusted the Taper wedge.. and now my Y-slide is moved with only two fingers and not enough force... For comparasion i would say i have reduced 50% force for movind the slide by loosening the taper wedge... I also checked the slope and it was un-noticable... The slide is very very Free now

2- The same procedure was adopted for my X_slide and it is also improved 50% from the previous...

Today i recalibrated X and Y axes as i have loosen the gibs.. I Did some real drilling on the SS-316 tube sheet of one of the exchanger we are fabricating... You can see the centre drills and two 8mm deep drills... The OTL (Outer Tube limit)is under 0.03mm... I also measure 14holes across and the commulative length is under 0.02mm...Now, I can drill SS-316 upto 33mm deep ...

The slides are very free moving after loosing the taper wedges..It seems that i have installed the linear rails
I am planning to make the new spindle with AISI 4140...Today I have hardened 03 different cylindrical pieces( dia: 1inch, length 1.5") of AISI 4140..
Each piece was heated to 850C and then one piece was Oil Quenched, One was Normal water Quench whereas the last one was quenched in the chilled water...
I have observed the longitudinal crack in the normal water quenched workpiece...

Following are the hardness results of 4140 test pieces..

A) Oil Quenched: 38.8HRC
B) Normal Water (Amb. temp): 54.1 HRC
C) Chilled Water: 49.8HRC

I cut half the option B, material and again taken the readings at the centre. I got 50HRC...That is excellent for spindle... For a good spindle the hardness must be in the range of 50~57HRC..

The Spindle is roughly machined out of AISI4140... I am going to Quench it on monday..

I am thankful to you for helping me...

Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: RICH on June 12, 2010, 10:04:45 AM
Khalid,
Nothing wrong with feel, i use a torque gauge to get values. Here is a link to my anal aproach
on a small lathe.
http://www.machsupport.com/forum/index.php/topic,12484.msg81868.html#msg81868
FWIW,
RICH
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: timskx1 on June 14, 2010, 10:43:54 AM
Hi everyone.  Tim here.  I am having a problem with the units on my mach 3 software.  I set it ti inches, but the machine is working in metric units still.  anyone have any idea what is going on?  Thanks all.
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: Hood on June 14, 2010, 01:54:21 PM
Hood
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: timskx1 on June 14, 2010, 02:25:02 PM
What is that?
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: Hood on June 14, 2010, 02:32:47 PM
It is your configuration file, you will find it in the Mach3 folder on your hard drive. If using the standard mill profile it will be called Mach3Mill.xml, if using a custom profile it will have the name of that custom profile. You will need to copy it to another location on your drive then rename so that the forum will accept it, suggest you rename to timskx1.xml
Hood
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: timskx1 on June 14, 2010, 02:43:30 PM
I am not in front of the computer with the mach 3 software on it.  That comp is at home.  If i get a chance tonight i will copy it to a flash drive and bring it in tomorrow.  Thanks
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: timskx1 on June 14, 2010, 02:45:20 PM
I am using the configuration that came with the cnc when  i bought it.  Seige KX1
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: Hood on June 14, 2010, 02:53:25 PM
Do you have a link to the sieg xml?
How did you change the units?
If you command a G61 then a G0X1 move in MDI does it only move one mm?
Hood
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: timskx1 on June 14, 2010, 04:05:02 PM
I will check tonight
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on June 23, 2010, 05:20:54 AM
I have started drilling SS-316 tube sheet 30mm thick:
Spindle RPM: 800
Feed: 1 IPM
Peck drill Cycle: Deep Drill
2.5mm cut per Peck
The drill retract above the work piece after each 2.5 depth cut.

HSCO drill: 8mm

After 37 holes contineously , Without sharpening the tool.. The drill break down on 38th hole..
Now after each 20 holes i am planning to sharpen the drill.
Time to complete One hole 30mm deep: 7Minutes
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: Hood on June 26, 2010, 11:59:10 AM
Looks to be working well :)

Think I would be spinning slower and feeding harder though.

Hood
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on June 26, 2010, 12:58:46 PM
Looks to be working well :)

Think I would be spinning slower and feeding harder though.

Hood
Yaa.. The system is working well now... Following is my experience:

1- The HSS drill failed on the Second hole... I kept the RPM 800 and G73 cycle with Peck 6mm.. It simply toasted;) Flood coolant was On... 2min/hole

2- The second bit is used was Carbide, It ran for 30 holes and then suddenly break into 3 pieces... Again G73 peck cycle but with 2.5mm peck... 2 minute/hole

3- I then used  HSCO drill and with G83 Cycle, lost it after 38th hole with 2.5mm peck... Coolant on.. 7minute /hole

4- Keeping all above experience in view, i again used HSCO drill but at this time G83 with 2mm peck (DOC) and after each 15 holes i sharpen the drill.. For this i added tool change command after each 15 holes in my Gcode.. i slightly changed the Gcode for downtime...
The above strategy went very good and i did above 100holes without breakage... 5minute /hole

5- I have HSS drills available, so i tried the same G83 cycle with them with 2mm peck and sharpening after each 15 holes..and i did 50 holes without loosing HSS drill.. 4.5min /hole

I have done 224 holes in 16.8 hours.
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on June 26, 2010, 01:27:24 PM
Started building new Spindle and its houseing.. The Spindle is off AISI 4140 hardened to 55HRC... and now it require grinding... The Vertical column is also in fabrication phase.. I will get red of complete Radial drill except the Cross-slides..
The New column is very sturdy..
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: Hood on June 26, 2010, 01:59:52 PM
New spindle etc looks like it will be a big improvement :)

I have never had much luck with carbide drills in stainless, 8% cobalts  are best for me,  you have to feed them hard as any rubbing at all and the stainless work hardens very quickly, I would probably spin an 8mm at about 600rpm and feed at 40mm/min in 316. I also try and make sure the coolant is pointed directly into the hole with a strong jet.
Hood
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on June 27, 2010, 01:32:35 AM
Hi Hood ,
I have now to enlarge these 8mm holes to 9.5mm... Now I am going to do it with Standard Drill Cycle (G81).. Is it right? what mm/min i should travel the drill and at what RPM?
Regards

PS:
or anyother suggestions for 9.5mm holes.!!!
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on June 27, 2010, 03:07:35 AM
Here is the updated pictures of spindle housing being machined on Boring Mill and the completed tube sheet.
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: Hood on June 27, 2010, 03:59:11 AM
Khalid,
Thats not a great situation to be in, I think the drill will grab a lot due to the small amount you are going to be removing, I think I would try an endmill to enlarge rather than a drill.

Looks like you have some nice big machines :)
Hood

Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on June 28, 2010, 11:07:05 AM
Hi Hood,
Today I finished the tubesheet drilling with final hole size 9.5mm..
You were right the drill grabed long swarf ..However I Gcoded to stop the machine after each 5 holes... Following was my strategy..

Spindle RPM: 400 RPM
Feed: 3 IPM
Peck Cycle: G73 with 3mm per peck
Time to complete One hole: 1minute 5 seconds

I drilled all the holes within 5Hours.. You can see the video in the following youtube link..
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: Hood on June 28, 2010, 06:09:41 PM
Looks to be working great :)

Hood
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on June 29, 2010, 05:47:48 AM
Today I just experimented drilling on Multilayered baffles of the exchanger. Each single  baffle has a thickness of 3mm, total baffles in One Bundle= 18. Total thickness to drill= 55mm. We have used 8mm HSS drill and after TEN thorough holes the HSS drill was sharp as new.
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: Hood on June 29, 2010, 05:59:27 AM
Do you machine the outer profile at a later stage? If yes, how do you do that, lathe?

Hood
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: khalid on June 29, 2010, 07:10:14 AM
We will make a fixture... We will insert bolts at any 5- drilled holes at outer periphery and will turn it on the Lathe...
Title: Re: What Steps/ Units Settings for Z-axis (Quill) of CNC Retrofitted Radial Machine?
Post by: Hood on June 29, 2010, 01:50:34 PM
Thought that might be what you would do :)
Hood