Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: biscuitbrothers on November 20, 2013, 11:00:14 PM
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Hey everybody! Besides my intro post, this will be our second. My comrade-in-robotics and I are going to use the same account to simplify things, to explain why I frequently reference "we."
Alright, so this is our setup:
CNCRouterParts.com Pro 4'X8'
Prewired Nema 34 1.8 kit with Gecko 201x' and a 5th axis capability
We haven't purchased the router yet - any tips on that would be welcomed. We'll be working mostly with wood, periodically with long run times.
Mach3, of course.
PMDX-126 2012-10-19 N4 PRO pre-set XML profile from CNCRouterParts.com
So the machine runs - we even were able to get it to simulate cutting out a skull & cross bones from some Gcode that came with the XML profile. There are some questions that linger though, after reading the Mach3 manual, watching some MachSupport tutorials, and referencing other materials.
1. I have established soft limits in the homing/limits settings, but the axes stop moving a couple inches before they reach the limits I've actually set up....not sure how to understand that.
2. In spite of establishing soft limits (currently inactive), the "red outline" of the table display the video tutorial suggests we should see does not exist. I have not been able to find any setting that makes this appear, and I have enabled "Machine Boundaries" in the ToolPath configuration to no effect.
3. When we load Gcode, it seems that the bottom left hand corner of the Gcode pattern is actually our X home positive - my impression from the tutorial video is that the bottom left corner in Mach3 should be your X home negative. I have not been able to find settings that reverse or correct this.
4. We have run a couple of tests with other Gcode, and in spite of Ref All Home for Machine Coordinates, when we activate the Gcode, it slams backwards into the bumpers and limit switches (running towards the negative) as though the pattern was extended far past the actual table. What am I doing dumb here? I can't wrap my head around where this mistake would be coming from.
5. I set a safe limit for the Z axis, but even after establishing that it will jog right past it as though I never set anything. This is kind of a general theme actually - the coordinates in my settings do not seem to respond exactly to my real world coordinates and I can't understand where the variance is. We tested the steps per unit that were preestablished by the provided XML profile and they were exactly correct. Where am I losing/gaining inches? Machine Coordinates should be highlighted red when I Ref All Home to establish the minus limits of the table, and that should serve as a good baseline for additional testing, correct?
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Please attach your xml so I can look at your config whilst I read your questions.
Hood
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Thanks Hood for your reply. I've included the link to the XML.
http://www.cncrouterparts.com/Mach3XML/PMDX-126%202012-10-19%20N34%20PRO.zip (http://www.cncrouterparts.com/Mach3XML/PMDX-126%202012-10-19%20N34%20PRO.zip)
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I need your xml as there may be settings changed from the one you were supplied.
Hood
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Ah, I see. I'll have to upload that this evening.
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We haven't purchased the router yet - any tips on that would be welcomed. We'll be working mostly with wood, periodically with long run times.
Whats the price range? On the cheap side, I like Porter-Cables only because of the collets available here: http://precisebits.com/products/equipment/porter-cable_0429_collets.asp?tsPT=!!!Porter-Cable_0429!!!Collet!!!PG!!! (http://precisebits.com/products/equipment/porter-cable_0429_collets.asp?tsPT=!!!Porter-Cable_0429!!!Collet!!!PG!!!)
However the bearings in the P-C's don't last all that long.
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We anticipate the router will see some long run times and a significant amount of use, so we're not sure what we need to shoot for yet, but I think purchasing a starter router is not out of the question. Thanks for the suggestion!
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Here is the link to view or download our XML profile:
https://drive.google.com/file/d/0B9tPQDmW2J6aYlhGMHZpZmdrX0k/edit?usp=sharing
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1. I have established soft limits in the homing/limits settings, but the axes stop moving a couple inches before they reach the limits I've actually set up....not sure how to understand that.
It is normal to have X and Y min and Z max as zero and X and Y Max as the value of your travels and Z Min as the value of Z travel but as a negative value.
2. In spite of establishing soft limits (currently inactive), the "red outline" of the table display the video tutorial suggests we should see does not exist. I have not been able to find any setting that makes this appear, and I have enabled "Machine Boundaries" in the ToolPath configuration to no effect.
If you press the Display button and then Regen you will move into Table view which should show the area covered in your soft limits.
3. When we load Gcode, it seems that the bottom left hand corner of the Gcode pattern is actually our X home positive - my impression from the tutorial video is that the bottom left corner in Mach3 should be your X home negative. I have not been able to find settings that reverse or correct this.
Which direction do your axes move when jogging positive?
Which direction does the machine move when homing?
4. We have run a couple of tests with other Gcode, and in spite of Ref All Home for Machine Coordinates, when we activate the Gcode, it slams backwards into the bumpers and limit switches (running towards the negative) as though the pattern was extended far past the actual table.
Sounds like you have axes or possibly homing reversed, answers to previous questions may help establish which.
5. I set a safe limit for the Z axis, but even after establishing that it will jog right past it as though I never set anything. This is kind of a general theme actually - the coordinates in my settings do not seem to respond exactly to my real world coordinates and I can't understand where the variance is. We tested the steps per unit that were preestablished by the provided XML profile and they were exactly correct. Where am I losing/gaining inches? Machine Coordinates should be highlighted red when I Ref All Home to establish the minus limits of the table, and that should serve as a good baseline for additional testing, correct?
You do not seem to have home switches on Z so it will be set to machine zero where ever your Z is when you press Ref All. Because of that you will have to make sure that the Z is fully up before you press the RefAll.
Hood
Hood
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Most of these issues sound like you're origin (Machine coordinates 0,0) is not where it's supposed to be, or possibly where your g-code thinks it is? Or, you may have one or more axis reversed. COuld also be an issue with offsets.
2) The video used a very old version of Mach3. I don't think the red outline is used in newer version of Mach3.
3) The lower left corner should be X zero Y zero. Where are your home switches located? In Config>Homing Limits, "Reverse" changes axis direction, and "Home Negative" reverses homeing direction. If you're homing to 0,0, the X should home to the left, and the Y should home toward you.
4) Again, I think you have your origin set wrong/ axis reversed.
5) What do you mean you have a "safe limit" set? Do you mean soft limits? If so, do you have a limit switch at the top of the axis which sets Z zero at the top, with downaward travel being negative?
You don't have to have Machine Coordinates selected when doing Ref All. Ref All (homing) is always done in Machine Coordinates. Again, it all comes down to where your switches are, and how you have Mach3 configured to use them.
The more info you can provide, the easier it is to help.
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I can only speak to a couple of these comments without being in front of the machine:
1. We do not have a limit switch on the Z but we do have a limit switches everywhere else. I have tried to establish soft limits and enable the "Safe Z" feature but it does not affect the travel of the Z.
2. I did at one point think we might have the axes reversed, but when I clicked Home Neg on X Axis settings, it decoupled the slaved A (X Home) axis and torqued the gantry as the x and x home motors moved in opposite directions. We had to replace the gantry riser plate, as it bent the steel.
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1) You really need a home switch at the top of the Z axis to use the SafeZ feature effectively. Otherwise there's no sure way for Mach3 to know where the extents of Z travel are.
2) When you have slaved axis, all settings on the COnfig >Homing/Limits screen must be set exactly the same for BOTH the master and slave axis, or the two sides will move differently.
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2) The video used a very old version of Mach3. I don't think the red outline is used in newer version of Mach3
You dont get a red outline now but you do get a bounding box which is defined by your soft limits, see screenshot.
Hood
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biscuitbrothers
Can you please tell me which way the gantry moves and which way the DROs count when jogging each axis.
For example jogging X from Left to right does the X DRO count up or down, same for Y and Z.
Also where are your home switches?
Is X at left or right end?
Is Y at front or back.
Hood
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Bah! Nothing to read here. :-X
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Hey everyone thank you so much for your feedback. I think between all the different comments, we were able to wrap our heads around what was happening with regards to Table Display, homing and soft limits. I have attached a screenshot of our new settings.The table is now behaving mostly as expected after selecting both Reversed and Home Negative for X, Y and A, and reversing the Z. We've set some pretty conservative soft limits for the time being while we experiment.
There are a couple questions outstanding now. The first is regarding the Z. I have tried to Zero the Z to Machine coordinates in our upper limit, but it will not "zero", instead displaying on the DRO where it believes it is at. When machine coordinates are not selected, we can zero the Z value, but how does this correspond to our soft limits?
The second question is regarding running Gcode. The table display shows now in correspondence to our soft limits, but when we load G code, it is still outside of the table limits and I cant figure out how to move the toolpath within those limits. I have jogged the axes around and regenerated the toolpath, but it never moves the drawing within the table limits, it always stays on the bottom left corner outside of the limits. What am I misunderstanding?
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A couple things about the Z axis. You can't zero the machine coordinates with the zero Z button. The only way to Zero an axis is to Ref or Home it. You need to jog the Z axis to the top of it's travel, and click the Ref Z button. This will set Z to zero in machine coordinates at it's current position.
Your Z max softlimit is set to 1. The maximum your Z can ever travel is to 0 (the top of Z travel is zero). You Z max should be -1 or something similar.
And, while it has no effect if you don't have a Z axis home switch, the Z axis "Home Negative" column should have a red X, as the Z axis always homes positive (up).
As for your g-code. After you load it, go to the Limits screen and tell us what the program limits DRO's show. Do you have any offsets set?
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Okay, I have made recommended changes to the Z and it is now "zeroing" properly. To be clear, when we Ref All Home the Z axis never moves, only the X and Y. You mentioned hitting the Ref Z button - I can't find anything like that. Did you just mean Zero Z?
As for the g-code, what limits screen are you referring to? We have not established any work offsets and as far as the Offsets tab goes, the DRO's are all 0.000
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I've been playing with the offsets and the soft limits and I think we've got that figured out now too. Previous questions regarding our discussion of the Z remain. Thanks so much!
- I
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If you jog the Z to the top before you Ref All Home, then you're all set. There's a Ref Z on one of the other screen pages, but Ref All Home will set the Z zero as well, at it's current position.
You use the Z zero button to set the program Z zero at the top of your workpiece.
Sorry, the Program Limits are on the Toolpath screen (I don't use the stock screens).
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We're up and running. Spoilboard tomorrow. Thanks everyone for your assistance!
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We're surfacing the spoilboard today, and the task immediately following will be to engineer our clamping system to secure material to the table. I am not certain of the terminology I should be using, and I would like to find a specialized resource to look at our options. Can someone direct us to a website or store that would carry the types of clamps/pressure feet we need to evaluate? What is the proper terminology?
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Other than very expensive vacuum options, I'm not aware of any commercially available "clamps" to be used for hold downs on a CNC router. Everything I've made has been made by the users.
You might want to spend some time at cnczone.com reading through the forums to see what others have done.
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Odd's are you will end up making a lot of your own clamps and jigs. One thing that has served me quite well over the years is to use nylon bolts and wooden clamps. That way if you make a mistake somewhere, you don't ruin an expensive bit by trying to cut through steel. If you look on ebay you can find bags of 100 for a few bucks.