Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: GTRacer on May 29, 2008, 09:31:34 AM
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Hello all,
I know the very rudimentary basics of how the CNC machine works. My specialty is AutoCAD and MasterCAM. Mach3 is totally new to me as well. Our CNC machine is a ShopCAM from Lindsay, ON and apparently they went bankrupt and are no longer in existence as of just this past week. So I'm on my own to troubleshoot the machine.
A little on my setup:
x150 y64 z7 router table
Colombo 7.5hp spindle
Microstep Stepper motors
- X Vexta PK2913-F4.0A 2-Phase 1.8degree/Step
- Y Vexta PK2913-F4.0A 2-Phase 1.8degree/Step
- Z Vexta PK296-F4.5A 2-Phase 1.8degree/Step
Mach3 R2.0.037 running in Vista (which runs fine it seems)
My first area of confusion is this. When I first started the process of learning the machine I noticed that there was a much newer releases of Mach3, so I DLed it and installed it. The ShopCAM guy came by and was kinda upset that I had did that. He said that the newest release was no good and the machine wouldn't work right, so he reverted it back to the R2.0.0037 and ran some sort of driver tests (not sure what he did) to verify that the machine was ok.
Questions:
- Is that the case or should I be running the latest version to get the best results?
- If I do upgrade, how do I do that without losing any vital setup information like motor steps per pulse and that critical sort of info?
Me second area where I need assistance is with CV and rounded corners. I can only get the square corner cuts I want right now with Exact Stop, but I've been warned by my MasterCAM people that it is really hard on the CNC machine. They told me I needed to play with accel/decel curves to get what I want. I guess this pertains to my question about release versions as well.
- Does the latest version of Mach3 handle CV better than my older release?
Thanks for any assistance and if I need to provide anymore information to help clear my situation up just ask.
EDIT: Added the actual stepper motor specs.
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Mach 3 is under continual developement, and at any time there are several versions available.
If you go to Downloads, you can see what is available. Tou can download an old version, download the latest lockdown version, or download the latest version under development.
If you are wanting a serious version for serious work, there is one rule - If it not broke, don't fix it - so if the versionof Mach 3 that you have does all that you want, stick with that.
If you want the latest version that is "guaranteed" as far as possible, then use the latest "Lockdown Version". This will not change - and if anything goes wrong, you can download it again and get the same program.
If you want to be up there with the boys you can have a version that is still under developement - but if you download it again, it may have changed.
I personally use the latest "Lockdown " version.
You should be able to download the latest "lockdown version" and retain all your XML file and settings. In your case you do not say whether the version you downloaded was a "lockdown" or one under developement - so I cannot comments of the ShopCAM guys remarks.
As far a CV is concerned, this is an old problem and you should understand the difference between Cv and absolute stop.
If you are to cut a "square corner" the your axis(s) must travel to point A and then, instantaneously travel to point B, leaving (apart from problems with the diameter of the tool) a sharp corner. The only way the machine can do this is to come to an absolute stop in the direction it is travelling, then having put on any backlash required, set off in the new direction.
On my machine, with relatively slow travel, it might not be noticable (except for backlash which is terrible), but the faster your machine is, the more noticable it becomes, since the cutting head (or the table) has to accelerate to speed, then decelerate to a stop, then accelerate to speed and so on.
If you use CV, then as the machine decelerates to a stop in one direction, it also calculates and implements accerleration in the other direction - and never comes to a complete stop - but it must, by definition, leave rounded corners on your work (as well as any for the tool).
You cannot get square corners with CV - you must use absolute stop and put up with it, I'm afraid. You can alter the acceleration and deceleration parameters for CV to end up with as square a shape as possible - but you will never get to the "square corner"
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Probably best to use the latest lockdown version (2.63) but if the one you are using works fine then stick with it, the latest Dev versions seem to work fine and have bug fixes but if you dont have problems its probably not worth updating until they become lockdown.
Motor setup, pin setup etc is all stored in the xml file, it should remain intact after an upgrade, if it doesnt then you should be able to go back to a previous XML by going to the Operator menu and choosing restore. However it is always a good idea to copy your xml and keep it on another disc or computer, that way if your hard drive crashes or you get a new computer you can restore all your settings by pasting the xml into the new computers Mach3 folder.
You can set up the angle at which CV works and which it doesnt, this can help for sharp corners, you will find the settings on the General Config page from the Config menu.
Hood
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Thanks, I played with the feedrates and acceleration for all 3 axis to fine tune as much as possible. I ended up with:
X
feedrate = 400 in/min
acceleration = 60 in/min/sec
Y
feedrate = 400in/min
acceleration = 60in/min/sec (I could go faster on Y, but I thought it should be equal to the best i could get out of X?)
Z
feedrate = 40in/min
acceleration = 10in/min/sec
I'm just going to go with Exact Stop and forget CV mode then. I'm cutting $1000 a sheet aircraft honeycomb panels that have to be exact, rounded corners of any sort are unacceptable.
I believe my version of Mach3 is a lockdown version.
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I wanted to revive this post as I have some serious problems with Mach3 and my CNC router manufacturer is no longer in existence. I'm on my own to troubleshoot this machine. I've included a picture of the entire machine for reference.
1) First off, I'm having some axis woes. I discovered that when ShopCAM installed and setup the machine initially, they never bothered to calibrate steps per pulse for each axis, so everything was being cut half an inch too big. Using a dial indicator, I used the Axis Calibration tool on the Mach3 Settings screen to set the X, Y, and Z axis dead on, with a repeatability of +/- .0005". When I run a program, which I did one with a 1/2" diameter bit and then a different program with a 1/4" diameter bit, the Y axis adds exactly 1/16" of an inch to the part, the X axis cuts perfect. That's axis problem number one.
2) Axis problem number two is what I would call Z axis drifting. To cut my part I specify the exact Z thickness of the part, and add .050 for breakthru, which is overkill, but the part still ends up with an onion skin once I get about 18" along the X axis. See the attached picture of a pocket that was cut where the bit should have been at the same Z depth the entire time, but it drifted. The other picture is of various cuts that were all specified in the code to be the exact same depth, but notice the variance, the further ones even lifting completely above the spoiler board.
3) I've unchecked the boxes relating to overwriting my G54, but if I shut off the machine for the night, it will make the G54 X0Y0Z0 match where ever the machine was sitting when it was shut off. Right now I just bring it to X0Y0Z0 before shutting it down. Is there another way to save the position? Also related is machine coordinates. Does the table not have exact machine coordinates that are fixed, always the same? I ask for two reasons. One the machine coordinates change each time the machine is shut down. And two, the other day, between running two parts, the exact same part, the table suddenly came up with a new value for G28 and instead of moving up and preparing itself to run the program, it dropped down to well below the table's surface, fortunately off the X and Y axis, so it was spinning in the air, but without a quick E-stop right then, it would have moved into cutting the actual table.
I have another issue, but I'll add that one in a bit.
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1) First off, I'm having some axis woes. I discovered that when ShopCAM installed and setup the machine initially, they never bothered to calibrate steps per pulse for each axis, so everything was being cut half an inch too big. Using a dial indicator, I used the Axis Calibration tool on the Mach3 Settings screen to set the X, Y, and Z axis dead on, with a repeatability of +/- .0005". When I run a program, which I did one with a 1/2" diameter bit and then a different program with a 1/4" diameter bit, the Y axis adds exactly 1/16" of an inch to the part, the X axis cuts perfect. That's axis problem number one.
Make sure you dont have any scaling on the axis that is giving you problems.
2) Axis problem number two is what I would call Z axis drifting. To cut my part I specify the exact Z thickness of the part, and add .050 for breakthru, which is overkill, but the part still ends up with an onion skin once I get about 18" along the X axis. See the attached picture of a pocket that was cut where the bit should have been at the same Z depth the entire time, but it drifted. The other picture is of various cuts that were all specified in the code to be the exact same depth, but notice the variance, the further ones even lifting completely above the spoiler board.
Check to make sure your "Spoiler Board" is sitting correctly on the bed and that it is running true with regards to your axis. You could do this several ways but the easies would be to start at one end and move the cutter down to just under half an inch and then move the axis up slowly and slip a 1/2" block under, when the block just slips under stop jogging up and confirm that the block is a nice sliding fit. Then jog to another area of the table without moving the Z and see if the block slips under with the same fit. Repeat this all over your table and see how good it is.
I am not experienced with routers but I think the standard thing to do is when you place the sacraficial plate (spoiler board) on the bed for the first time you cut the surface all over to true it up to the machines axis.
3) I've unchecked the boxes relating to overwriting my G54, but if I shut off the machine for the night, it will make the G54 X0Y0Z0 match where ever the machine was sitting when it was shut off. Right now I just bring it to X0Y0Z0 before shutting it down. Is there another way to save the position? Also related is machine coordinates. Does the table not have exact machine coordinates that are fixed, always the same? I ask for two reasons. One the machine coordinates change each time the machine is shut down. And two, the other day, between running two parts, the exact same part, the table suddenly came up with a new value for G28 and instead of moving up and preparing itself to run the program, it dropped down to well below the table's surface, fortunately off the X and Y axis, so it was spinning in the air, but without a quick E-stop right then, it would have moved into cutting the actual table.
Does your machine have homing switches? The answer to this question will determine how you will proceed with this.
Hood
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Make sure you dont have any scaling on the axis that is giving you problems.
Mach3 is showing no scaling on the main screens, but is there somewhere I should be checking that?
Check to make sure your "Spoiler Board" is sitting correctly on the bed and that it is running true with regards to your axis.
The table is out by a very small amount, which is why I decided to go with .050 break thru, that way it'll be really deep at the "high" end and shallow, but should still be right through at the low spots. That doesn't explain the picture with the roughly 6" pocket that has a single Z depth and the router cut the path while drifting on the Z.
Does your machine have homing switches? The answer to this question will determine how you will proceed with this.
The machine does have a homing setup, when I tap the home key on my keyboard, it moves up into a nice safe position. It's the G28 command that is in the NC code that is the concern I have.
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My ideal is you calculate first, and use the axis calibration tool to check your answer is correct.
My X and Y are belt driven gears, my Z is a gear screw. I'll try to figure this out.
Mach 3 can then make allowances for tool diameter. All tools MUST be entered into the tool table, and the tool number selected correctly
I have a single spindle, each tool change is a new program to keep it simple and allow for the top of material to be referenced after each tool change. I have no tool info saved in Mach3, MasterCAM X2 takes care of all the tool offsets. However if the issue was with tool offsets, why is the X axis perfect and the Y axis out?
Wait a minute, where did your reply go jimpinder....
I agree with Hood about your Z axis - Is is Z moving, is is your table slightly out of true. I mounted a steel (6mm) plate on my table, and had the machine skim it true to the axis one evening. You can write the program and leave the machine to do it
The table not being level doesn't explain the 2nd picture above. That pocket was cut at one specified Z depth and it ended at a different level then it started. The Z is clearly "drifting" as the machine moves, what would cause that variance?
Your machine has two DRO readouts on your axis. One is machine co-ordinates and the other is program (or work) co-ordinates. When the machine co-ordinates button is lit, the display is machine co-ordinates, when not lit, program co-ordinates (and you can toggle between the two.
The machine MUST know where it is. There are two ways to tell it. (and you probably know all this)
One is have a set of home switches fitted. If you then press "Ref All Home" the table and the cutter will settle to these switches. The machine-cordinates will go to zero. The machine is happy - it knows where it is. Is is not likely that these home switches will be in a convenient position for useful work to take place, and therefore the table and cutter will need movng.
You can - as you seem to be doing, use an offset - and then tell the machine to go to it's new 0.0.0 position - now your machine-co-ordinates will show the offset, program co-ords will show 0.0.0 - and you can run your program.
Alternatively you can move the machine to a convenient position to start your program, ignore the machine co-ords, set the program co-ords to zero and start.
In Mach 3 machine co-ordinates can only be zeroed by using "Ref all Home". There is a problem in that if no home switches are connected, you can still "ref All Home" - but all that will happen is that the machine co-ordinates go to zero - whereever the machine happens to be. If there are no offsets set, I think it takes the program co-ordinates to zero too.
You may be finding (if you have not set up the homing switches) that this is causing your offsets to change, if you inadvertently zero the machine co-ordinates.
I'll go and take some pictures of the Mach3 screens to help troubleshoot what is going on, I'm really lost.
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Does the Z DRO reflect the ammount of drift ? Or does it stay at the programmed value ?
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Sorry the second pic wasnt showing at the workshop so never noticed that it ended up in the same X Y but higher in the Z.
Make sure there is no scaling set in your code, G51 Y*
Ok as you have home switches first thing you want to do is go to homing and limits and choose the Auto Zero option. Next go to General config page and have the Persistant DROs and Persistant Offsets checked, also make sure you dont have Copy G54 to G92........ checked.
Next time you start Mach and do your homing move it should set the machine coords to zero but your work offsets should reflect you last saved offset.
Hood
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Does the Z DRO reflect the ammount of drift ? Or does it stay at the programmed value ?
That is something I haven't noticed, I think I'll be running a test program this afternoon to check to see if the Z drift is visible on the DRO.
I took some pictures, first off are the shots showing the drive mechanisms. The first is the Y axis. The second is the Z axis. The third is the X axis and the 4th shows the driveshaft that runs underneath to move the other side of the gantry along the X axis.
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These pictures show the G54 X0Y0Z0 I set
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These pictures show the position achieved by hitting the home key on the keyboard.
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And these pictures are as much of the settings as I thought might be needed to start the troubleshooting process. If you want to see any other screens, just let me know and I'll go take pics.
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the rest of the pictures
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Hi, GTRacer
Would you post the DXF & G-code file for for this part.
There could be some posting errors in your G-code.
Nice Router !!
Thanks, Chip
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GTRacer, Are you certain the bit isn't drifting in the collet? THis can be tough to catch sometimes. I have sent you a personal message.
Brett
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The company we purchased MasterCAM X2 from directed us to talk to a router table company that knows Mach3 and our machines. I sent him all the pictures above plus some more of the guts of the controller box. He replied back with a few numbers to tweak in the motor tuning and the machine now cuts accurately on the X and Y axis. There's still some issues to work out though. Thanks for all your input so far.
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what are the issues still needing worked out?
Hood
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1) Because I'm cutting FibreLAM panels, I'm cutting with an oscillating Z depth to avoid burning the bit. MasterCAM can automatically add a linear oscillation, something that resembles /\/\, or a high speed curve like a Sine curve. Either way results in very abrupt movements because even though it's in CV mode and no longer rounds my corners, it's treating both the linear and the High Speed oscillations as Exact Stop on each line of code. How do I set Mach3 so that I get perfectly square corners and yet don't end up with Exact Stop style movements.
2) Unfortunately because I had to get a panel cut, once the nested series of parts didn't work I simply overworte that code with a single part at a time program, so the original code doesn't exist, but MasterCAM and the Mach 3 screen both showed the correct movement, but once the parts were being cut, the router ignored a Z move to out above the panel and so when it did a rapid to the next slot it ripped right through the parts and then went back to business as usual. In fact it cut the rest of the slots and then the outside edge of each panel without any further incident. What on earth would cause a machine to ignore a line of code clearly visible on the screen? I'll try to recreate that program in MasterCAM.
3) And yesterday after I made the changes to the auto zero in the homing limits, I discovered the hard way that the table would go right past the limit switches and hit the physical end of the track. But it was rather random, sometimes it would pick them up as normal and other times it would pass right by.
I did find out some interesting things from this router table company that is helping me over the phone. He knew that my stepper motors lose all torque past a certain rpm so I needed to keep my feed speeds down to compensate. He knew what values should be in the step pulse and direction pulse in the motor tuning. I have to give him all the details on my table's movement gears and tracks and the Z screwgear and he's going to calculate exact steps per pulse for me.
EDIT: I can't remember the size of the piece of material I had that gave me the nesting layout that cause the issue, but here's the NC code for a single part. the table clearly ignored a move exactly as line N300, then it ran line N310, which ripped through the part, then it may or may not have ignored the Z.1 move before continuing merrily on its way cutting all the other slots and edges.
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1. I am not sure you will manage to do that, messing with the settings to suit your particular machines rigidity and Velocity/Acceleration may find a sweet spot but it will be trial and error.
2. Sorry cant think of anything that could make this happen.
3. Mach should always stop at your limits, how are they set up, are they normally closed asn all connected to one pin?
What Version of Mach are you running?
Hood
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Mach3 can't follow a sine curve without thinking that it needs to treat the smooth transitions from curve to curve as Exact Stop? ???
And as far as the limits go, I'll add some pictures for detail.
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Hi, GTRacer
Your Z axis Velocity and Acceleration may be set to high in Motor Tuning.
The G00 Z.25 moves at "max vel & accl" values in motor tuning.
Run the Att. G-code file I changed your G00 Z.25 to G01 Z.25 F40.
Chip
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Yes Mach can follow a sine wave in CV mode, the problem arises when a machine cant follow a sharp corner due to the velocity and acceleration relationship of the axis. This is where you may need to use the CV settings on the Config page and that is why I said it is specific to individual machines and that messing with the settings will find a sweet spot for your individual machine. As an example, I dont need any CV settings in config for me to be able to do sharp corners in CV but a fast light machine may need them.
Hood
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Here is a good read on CV, the related settings and their effect.
http://www.machsupport.com/docs/Mach3_CVSettings_v2.pdf
Might help, maybe you have it already.
RC
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I was wondering if there was a possibility that the accel and velocity of the Z was too high. I ran some tests yesterday, one of them was simply to bring the tool down and zero it off the table as the new Z zero. Then I began typing in manual lines of code, just random G00 X Y Z movements all over the table. I then brought the bit back to the exact spot I touched off of and it was out 3 to 4 thousandths. I also ran a cutting program after that and the Z depth "drifting" was worse than ever. The material was 1/2" MDF that varied between .504 and .518. Some Z cuts cut all the way through and others left varying thickness of material left.
EDIT: If the table was actually the problem, the bit should have cut the proper break thru at the XY spot that I zeroed the Z, but by the time the tool came back to that corner it was leaving a thin skin of MDF as it made its pass.
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Does the Z DRO reflect the ammount of drift ? Or does it stay at the programmed value ?
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I keep forgetting to watch that, I have one more sheet of parts to cut in about a half hour, I'll stop being mesmerized by the machine actually making dust instead of the usual just collecting dust and watch the Z DRO intently.
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The Z DRO reads spot on exactly where the code tells it to be, but the actual cuts vary, plus I verified that the bit isn't moving in the collet.
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Mach counts the pulses at the port from what I understand, so if the DRO is reading right then its a hardware issue. Have you tried swapping out drives and motors from axis to axis?
Hood
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I can't swap motors I don't think, the Z Axis stepper motor is a smaller motor than the X and Y, and I have no idea how to change around the drives? I have been put in contact with a company out of Cambridge Ontario, maybe we'll have him come up here to really check everything out.
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if you have access to a dial gauge set it up to measure the z platten holding your router , and see if it is infact any movement in your slides or ballscrew etc ,
it could even be your router motor bearing etc , may be worth a look
Dave
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I'm simply cutting deeper than needed to make sure the bit cuts all the way through. Things are working much nicer now, between the contacts I was given, they've gotten me fairly settled. I do have a new question unrelated to the above issues. Does anyone cut ATR/FibreLAM panels? I'm trying to find out if there's a way to cleanly router out these panels without the inner honeycomb fraying and leaving messy edges. The pictures attached are the router bit I'm using and the resulting edge finish of the honeycomb. The woodshop guys here are very keen to point out that they can cut the panels better by hand with a tablesaw.
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This should be interesting! That is going to be tuff i would think with a rotary tool. I have heard of freezing rubber with a crogenic procedure so it can be machined and hold a nice finsh. I'll ask around too, but this is a tuff one I think. Hopefully someone else will have a quick fix. Have you asked different bit suppliers for suggestions?
Brett
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How about a small high speed circular saw mounted on the Z using Tangential control ?
Internal corners would be a prob but outside cuts might be OK.
Just a thought,
RC
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High Helix cutter may help or may make it worse LOL
Hood
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Well I'll be cutting a bunch of parts today that make up the Aft wardrobe in our bigger jets. I'm going to try another style bit we have here, Onsrud 67-324, here's Onsrud's Composite catalogue, https://www.onsrud.com/oc/pdf/THINKComposites.pdf
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In that Onsrud catalog, they list a Honeycomb cutter 30-300 series- Have you tried that?
Sid
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Me second area where I need assistance is with CV and rounded corners. I can only get the square corner cuts I want right now with Exact Stop, but I've been warned by my MasterCAM people that it is really hard on the CNC machine. They told me I needed to play with accel/decel curves to get what I want. I guess this pertains to my question about release versions as well.
- Does the latest version of Mach3 handle CV better than my older release?
Didn't have time to read the whole thread, but two other ways to minimize or get rid of round corners with CV mode are
1) Use G41/G42. This will give you a toolpath with corners having the same radius as the tool, which gives a square corner with a rounded toolpath. The larger the tool, the more luck you'll have at getting rid of the round corner.
2) Create offset toolpaths with a radius corner the same as the tool. Basically create the comped path in your CAM package.
Both methods do the exact same thing, and if your accel is fast enough, they may work for you.
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Thanks, I played with the feedrates and acceleration for all 3 axis to fine tune as much as possible. I ended up with:
X
feedrate = 400 in/min
acceleration = 60 in/min/sec
Y
feedrate = 400in/min
acceleration = 60in/min/sec (I could go faster on Y, but I thought it should be equal to the best i could get out of X?)
Z
feedrate = 40in/min
acceleration = 10in/min/sec
I'm just going to go with Exact Stop and forget CV mode then. I'm cutting $1000 a sheet aircraft honeycomb panels that have to be exact, rounded corners of any sort are unacceptable.
I believe my version of Mach3 is a lockdown version.
Hi, I have the same router only 52-100 shopcam. I got the frame and built my own controller. I am sure I know what company you work for and I am in the same city. I was wondering if you still have the shopcam? and if you do, what kind of motor setting you have in the motor tuning? I am trying to mill multiple circles and the circles generally start ok then gradually get worse then the machine totally loses position in the X axis by about an inch. I am not sure if I am running the machine too fast to mill circles (100in/min) and this is causing missed steps. can anyone help?
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Hello MarkA, I will take a look at my settings today or tomorrow and get back to you. The table has been running fairly trouble-free for the last two years, so I can't even remember what any of the settings are. The only issue we've had with the ShopCAM table is that the entire carriage twisted and was cutting slight parallelograms instead of squares and there's no easy adjustment of it.
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I am glad to hear that it is running trouble free. gives me some confidence.
The First machine that ShopCam delivered to us was not square. I tried to fix it but I remember there was no adjustment. The machine I have now has been modified since then. the change is this: The 3 elongated holes that are on each end of the steel plates that hold the gantry(carriage), have been bored out. I noticed on our first machine that the elongated holes should have been 90 degrees from the way they are so that if it was out of square you could loosen the 12 bolts that hold the gantry and pivot it until square, then tighten them back up. I am still not sure how precise the machine is but it seems to be good enough for woodworking.