Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: Kendall.Miller on July 23, 2010, 07:40:59 PM
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I just received my new Syil X4 and have purchased a Mach3 license and am using the .XML file that Syil supplied. Everything seems to be going smooth, except for one thing...
When I cut a pocket, it is under size by about .002 in/in and bosses are over size by about .001 in/in, (am assuming) the variation is probably the spindle (or) collet run out plus what ever backlash I have...
I have checked the spindle run out (about .0005) and have check the X Y movements, which shows about (on a average) .006 short in 4"...
Art, what area gets changed and how do I do it...
Kendall Miller
Fun Dimensional, Inc.
Leander, Texas
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Ken,
Make note of the original steps per unit. Now go to the settings page and calibrate each axis ( info in the manual ).
( the steps per inch, velocity and acceleration can be changed in CONFIG>MOTOR TUNING )
See if there is any difference and be meticulous in what you do. You may want to tweak the steps per unit.
I would suggest that you check it out some by first seeing what the steps per unit should be for say a max travel, then 1/2 the max travel,
and then see what it looks like at a range of motion you may normaly be working at.
Don't know what kind of balls screws are in your machine and the associated specs for them. Even lower spec'd ones will be in the +- .003" / ft
and they would be very repeatable if backlash was neglegable.
You need to have confidence that the steps are correct, machine is adjusted nicely, and then you can adjust machining practice to achieve desired results.
RICH
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If your tool is .001 undersized you'll get similar results.
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R
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Oh sorry for my post above, was using the netbook to view the forum and dont know how the hell I managed to do that ;D
Hood
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As soon as I saw the problem, I purposely chose a large stubby tool that would not flex and it measured exactly .375, I ran a program that would cut a 1.500 x 1.500 pocket, and one that would would cut leaving a 1.000 x 1.000 boss standing...
I am checking the pocket with gauge blocks and the boss with a 1" mic...
The machine has class P5 ball screws, since they brag about it, I assume that is good...
So it sound to me that you are saying that I need to decrease the number amount of steps in the [Config>Motor Tuning], correct? Is there any other item that this will effect and need to be addressed in the [Config] when I do this?
Regards,
Ken
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The machine has class P5 ball screws, since they brag about it, I assume that is good
Yes they are good...P5 lead accuracy is +-23um / 300mm
The tighter the tolerance on milling, the more practical machining items like, coolant / cutting fluid, type end mill, cut passes / direction, etc come into play.You will find that there can be a difference by just not using a cutting fluid for the same material or the condition of the end mill.
If the spindle run out is a half thou, and then the collet has some eccentricity, end mill sticks out some, then before you know it you could have a thou run out at the tool cutting edge. Actualy machining something is good, but, you don't change the steps per units based on it.
I said note the original settings, as i will assume that their steps per inch are correct, and thus you want to confirm.
So take your time and reafirm table movement by using a dial indicator or whatever as long as the method is accurate.
decrease the number amount of steps in the [Config>Motor Tuning], correct
Yes....but why not use the calibrate axis available in Mach ( it is fast and very accurate ).
Is there any other item that this will effect and need to be addressed in the [Config] when I do this?For the small step changes that you may make it will not have any affect on the accel or velocity
RICH
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As I stated in my first Post (1st [Post] ever):
RE: with more detail
I checked the X movement out measuring 6" ((2) 1-2-'3' blocks against a stop, measuring leading edge to leading edge with an electronic indicator (same direction of travel)), Mach3 DRO = 5.994 (measured several times, always varied by about .001, this seemed to be the average)...
RE: set up
The 1-2-3 blocks were trammed straight with an indicator, secured, and checked with mic's to make sure the over all length was correct before the test measurements were taken.
Measured the Y movement over 4" travel ((2) 1-'2'-3 blocks), Mach3 DRO = 3.995 (average, using same set up as above))...
The test cuts were made in (2) materials, Delrin & Glass Filled PC, with the exact same results, the pockets were measured with gauge blocks, and the boss was measured with 1" mic.
What is my next step to correct this problem?
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Is your machine stepper or servo and what are your steps per unit?
Hood
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I am a novice, but all I see in the doc's is "Stepper per rev = 200", so I assume that I have Stepper Motors...
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Ok so its steppers now have a look at Config menu then Motor Tuning and see what steps per unit are for X Y and Z
Hod
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This mill is a Syil X4 Standard, the .xml file came with the machine.
Mach3:
Config>Motor Tuning
Axis Stepper Volocity Acceleration
X 10160 150 20
Y 10160 150 20
Z 10160 100.02 8
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Opps, Steps Per not Stepper
This mill is a Syil X4 Standard, the .xml file came with the machine.
Mach3:
Config>Motor Tuning
Axis Steps per Volocity Acceleration
X 10160 150 20
Y 10160 150 20
Z 10160 100.02 8
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Ok well that is not the issue, I was thinking maybe your steps per unit were close to 0.001 and that it was the nature of microstepping that was giving you the error but as your resolution is ten times greater then I dont think that is the case.
Have you checked the rigidity of the machine or in other words how much play is there in the slides, especially the Z axis.
Hood
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I can not feel any looseness in the gibs, I can see that it does move a little if I look out at the end of the slide, I think it is tight...
Though I can not find it again, I thought I read somewhere that Mach3 could be adjusted for accuracy.
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All:
Think I found the answer and will share it with everyone...
Improved Mach 3 Axis Calibration Video
http://www.youtube.com/watch?v=XkO5tc-jSxw
Kendall Miller
Fun Dimensional, Inc.
Leander, Texas
USA
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Kendall, Rich already told you about the axis calibration a few posts back ;)
Hood
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Kendall,
Yes you can make adjustments and you reply #15 is the axis calibration mentioned in one of my replies.
I believe you have 5mm ball screws:
200 steps / rev x 10 micro steps x 5.07614 screw turns per inch= 10152.28 steps per inch setting
10160-10152 = 8 difference
1/10152= approx .0001" movement per step.... so 8 x .0001"= say .001" difference if 10160 was used
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So that is the calculated steps, but, life is not exactly perfect.
So try 10152
" " 10146
" " 10140 and see what the DRO is compared to measured.
What the calibration feature does is the equivilant and i will remark that the affect of small changes in steps per unit are not linear.
Please note that there is no such thing as "zero backlash", may be small but you will have some....!
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Once the steps per unit are set and movement agrees with DRO. Then do some machining and see how it all goes.
You can change the velocity. For instance, see where the motors start to skip, say they skip at 180, then reduce your velocity to
70% of that and use 126 ( that gives you some head room for machining ) and you may want to fool with the accel in a similar manner.
Hope the above is more helpfull,
RICH
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Sorry if I am a dumb A55, I only have had this machine a few days and Mach3 a few more days prior to that... Maybe after I have played with it enough I will start to understand the things that ya'all take for granted that I should already know...
Bet I could of figured it out if anyone would of mentioned [Alt-6], look above the [Reset] icon dummy, the wizard does it for you... X is now set, it ended up @ 10167.5 (7.5 more steps per inch), working on Y...
Sunday Church (got a lot of thanks to give, and a lot of praying for help to do), Monday, I will be working on the flood coolant pump that came from Syil 'not installed' and with no instructions! Bet I will be just as dumb with this issue, with what I have read about over tightening wires will break the board, under tightening it will make it the machine fail, just can't wait to get into this project...
Thanks for all the help, you
made me dig into the basics,
I'm a more educated now,
Ken
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Ha ha dont worry about it, we all started at the beginning . Problem with getting a machine thats all set up for you when you buy it is you dont need to start at the basics unless there is an issue.
If you have a chance have a look at the videos, they give some good explanations of the basic things and often it sinks in better than reading the manual.
Hood
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I have tried reading the manuals (both set up & using Mach3), covers all machines, one is over 150 pages and the other is over 100 pages, and again using abbreviations that I don't know what he is talking about...
I have been viewing videos ever since I ordered the machine... Some I have to laugh at, I saw one guy blowing his machine off with an air hose, sending the debris everywhere, all over his computer and keyboard, all over his machine (including the vent holes (where it can get sucked up inside)), and am sure embedding them nicely in the ways also. This is someone who will be asking the question 'why' did my controller board short out... I'm dumb, but not that dumb!
This Has Been An Experience,
Ken
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I am meaning these videos http://www.machsupport.com/videos/
Hood
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Nope, never saw these movies, have never been to this page on the website at all, I have bookmarked and will review. Now I really feel dumb!
Ken
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The videos are mostly old so some things may look different as Mach has changed a lot but the basics are the same and they are worth a look especially as you advance and start doing macros and brains.
Hood
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Ken,
It's just takes some time and there are no shortcuts. Very difficult to sit down and read 150 page manual and expect to understand it.
Every thing is so interelated and as such it's extremely difficult to have a manaul written that keeps the thought train on track for a particular
item. CNC is certainly not plug and play. Mach is so configurable.
Sometimes trying to answer a question is like pulling a tooth, eventualy it comes out but can be a little painfull on the way.
You get stuck on something post and someone in here will be able to answer the question.
Heck, in time you'll be gumming it just like the rest of us! ;D
BTW, I am not even sure where or if the axis calibration via the Settings TAB is covered in the manuals.......and i was too lazy to look for it. ???
RICH
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Rich,
I am not a machinist by trade, I fell into it in 04 when one of my customers wanted me to knock off $500 dollars from his bill in exchange for a tabletop MaxNC mill, times were better back then in the US, we were getting over the 9/11 crash, so I said yes...
I am a Plastic Product and Injection Mold Designer, a couple years back I couldn't find any work and quoted doing some prototypes with my MaxNC, since then the Design Business has been paying less and work has been hard to find, and the Machining Business has been steadily been picking up. Hell, I can almost make a living again!
Now you know my background...
Regards,
Kendall Miller
Fun Dimensional, Inc.
Leander, Texas