[Za...] Posted August 2, 2019 Share Posted August 2, 2019 Hello all, I'm fairly new to CMMs and CMM Programming, but I've picked up what I've needed to fairly quick so far. However, I've run into an issue that I haven't been able to remedy yet. We have a Zeiss Contura machine with an RDS-CAA I'm creating a new program with an imported CAD .stp file and after I run through the manual alignment to set the base alignment to zero and get the probe facing in the correct direction on the screen (show probing object turned on), my sigma numbers are great on the -X and -Y planes, but terrible for my points being taken on the +Z plane and it's causing the machine to attempt to probe in places that aren't very close to what it should be. I've tried multiple styli and replaced each of those styli and re-qualified to try again without any luck. I'm starting to wonder if there's a connection plate issue or if there's actually something wrong with the machine itself, but I'm hoping I'm wrong and it's something simple. I included the X and Y sigma #'s as well as my sigma #'s for the probe I'm attempting to use. If there's any other information that's needed to evaluate the issue, please ask and I'll do my best to provide that information. Any help is appreciated. Thanks, ZachStylusInfo.pngY.pngX.png Link to comment Share on other sites More sharing options...
[Me...] Posted August 2, 2019 Share Posted August 2, 2019 What do the actual points of the feature look like? Open the feature in question, right click in the graphics window, and check "show actual points". This will give you a quick indication of what's going on with the surface. If the machine isn't driving to the correct location my first inclination would be an alignment issue. Also, if the part is rocking in any way or unstable when probing it could cause the probe to lose pressure against the surface and cause various issues with probing. Just shooting from the hip here. Robert Link to comment Share on other sites More sharing options...
[Za...] Posted August 2, 2019 Author Share Posted August 2, 2019 Robert, thank you for your quick response. The points on this picture are from the manual alignment, but when I try to execute just the +Z plane in CNC mode, it's far enough off where it crashes due to being off of the part. The part seems to be aligned correctly, at least it was aligned enough to run through all of the features yesterday morning. I have the part clamped down in 2 places, so I doubt it's moving.Nominal&Actual Points.png Link to comment Share on other sites More sharing options...
[Me...] Posted August 2, 2019 Share Posted August 2, 2019 Like I said, if the machine is going to the wrong location it's either that your alignment isn't stable and/or the part is so misshapen that it's missing the part and giving you the form error you're seeing. If you're aligning to 3 planes for your base alignment I would try using a plane for Z, and a line and point for X & Y and see if it improves instead of using 3 planes. You can always go back and measure them as planes and create alignments from them but I would steer clear of using all planes for your base alignment. A second option would be to create your base alignment using different features and see if you can get better repeatability on the probing. Robert Link to comment Share on other sites More sharing options...
[Za...] Posted August 2, 2019 Author Share Posted August 2, 2019 Okay, Is it maybe how I have it mounted that's causing the issue? I'm trying to figure out the best way to do this with the part design and our fixturing. Thanks again, ZachSetup.pngPrint.png Link to comment Share on other sites More sharing options...
[Me...] Posted August 2, 2019 Share Posted August 2, 2019 Did you try my alignment suggestions? Link to comment Share on other sites More sharing options...
[Za...] Posted August 2, 2019 Author Share Posted August 2, 2019 I tried to do it your way and it says unable to calculate alignment... I've never had any issues using 3 planes for a base alignment before though, can I ask why this could be an issue? Link to comment Share on other sites More sharing options...
[Ri...] Posted August 2, 2019 Share Posted August 2, 2019 Your side planes might be too small, and causing calculation issues. The simplest, but most effective alignment is a 3-2-1 alignment. A 3 Point Plane on the Top Surface A 2 Point Line on the longest surface edge (right side for your part looks good) A single Point on either the front or back surface edge. Link to comment Share on other sites More sharing options...
[Za...] Posted August 2, 2019 Author Share Posted August 2, 2019 I guess I was trying to keep it simple and have less alignments to do to get my locations, but as soon as I get a free minute, I'm going to try to get it aligned how you're suggesting and I'll update here. Thank you for your help, Zach Link to comment Share on other sites More sharing options...
[Me...] Posted August 2, 2019 Share Posted August 2, 2019 If it's unable to calculate the alignment with a simple plane, line, point then you definitely have an alignment issue. As far as using all planes, it's not always a problem but it can be. I've seen weird things happen not only with Calypso but with PCD and other software. It usually has to do with using a plane to rotate your base alignment to. A line is just 2 endpoints and resolves much easier than a plane, which has additional vector data to consider when it calculates the alignment. My workflow would be as follows... 1) Import CAD model. 2) Transform CAD model to the coordinate system that matches your desired Base Alignment if it's not already there. 3) Combine CAD features and Merge Faces with same geometry. 4) Create Base Alignment from top plane as Z+ spatial and Z origin, 2 point line on left side (-B-) as Y+ rotation and X origin, and a line/point on bottom as Y origin (-C-). 5) Run Manual and DCC on Base Alignment. 6) Program away. Robert Link to comment Share on other sites More sharing options...
[Ri...] Posted August 2, 2019 Share Posted August 2, 2019 Hmm... I don't know if that passes the smell test. A Plane-Plane-Plane alignment is a pretty straight forward Alignment to make. Which is why the CAD Cube is a great artifact to work with for beginners. The problem with a Plane-Plane-Plane alignment is when the Planes become small relative to the rest of the part. You have a 6" part, but you are trying to use a Plane that's only an 1/8" in length. That can become unstable, or just doesn't give a good representation of the part. Link to comment Share on other sites More sharing options...
[Za...] Posted August 2, 2019 Author Share Posted August 2, 2019 Please sign in to view this quote. Ah, now this is starting to make my wheels turn. What if I took points on both planes along the B datum as well as the C? I'll give it a whirl in the morning. I think it's about time for an adult beverage after today's struggles 🤣 Thanks again to those who have contributed, Zach Link to comment Share on other sites More sharing options...
[Me...] Posted August 2, 2019 Share Posted August 2, 2019 Please sign in to view this quote. I think we're saying the same thing, Richard. Edited to add: Look at the -Y plane. There's a 10 Deg deviation from nominal angle and a 5 unit deviation in X. Is this the plane you're using for rotation/origin in your Base Alignment? Link to comment Share on other sites More sharing options...
[An...] Posted August 5, 2019 Share Posted August 5, 2019 See attached.Contribution_05_08_2019_.pdf Link to comment Share on other sites More sharing options...
[Za...] Posted August 5, 2019 Author Share Posted August 5, 2019 So I tried running through this again on Saturday and just tried a couple more things this morning. I've tried all of our styli from the -Z direction and I'm getting bad sigma numbers no matter what, even though the styli all qualify with good sigma numbers. I'm going to try to shutdown the computer and requalify again, but I suspect there may be something wrong with the CMM probing in the -Z direction, since all of my other points come in perfectly. The machine is due for calibration in October, but we may have to move that timeline up. Link to comment Share on other sites More sharing options...
[Za...] Posted August 5, 2019 Author Share Posted August 5, 2019 Please sign in to view this quote. I am not sure what you are asking here? Those numbers generated automatically when I probed in the planes. (I have tried clicking in the points and probing in the points). Link to comment Share on other sites More sharing options...
[Za...] Posted August 5, 2019 Author Share Posted August 5, 2019 So, as soon as I restarted everything and went to qualify my styli, I received this error when probing the reference sphere with the master probe. I'm going to requalify everything and then I'll come back here with an update. Link to comment Share on other sites More sharing options...
[An...] Posted August 5, 2019 Share Posted August 5, 2019 Release all constraints and give the Gauss algorithm all the degrees of freedom he needs. See attached.Contribution_05_08_2019__.pdf Link to comment Share on other sites More sharing options...
[Za...] Posted August 5, 2019 Author Share Posted August 5, 2019 Please sign in to view this quote. How do I "Release all contraints" ??? I requalified all of my styli and everything looks good as far as the sigma numbers go, but I'm still having issues... I started a new program, imported the cad model, put the model in its correct orientation, selected my features for my base alignment (-X, -Y, +Z Planes like I've done with parts that are nearly identical to this), Executed my manual alignment, and these are the actual points it shows when I look at nominal/actual points... Link to comment Share on other sites More sharing options...
[Za...] Posted August 5, 2019 Author Share Posted August 5, 2019 So, here is where I am currently at... - All styli qualify great - No problem running other programs Is it possible that the CAD file is causing an issue? Is it possible that the part being probed is causing an issue? The only thing I haven't tried yet is probing everything from scratch and making the program without the CAD file. It's not necessarily what I am looking to do, but I'm thinking it could rule out the CAD file and/or the part being the issue. Link to comment Share on other sites More sharing options...
[Za...] Posted August 6, 2019 Author Share Posted August 6, 2019 Update: I'm having them make me another part and I'm going to give it another go again today. Hopefully I can get this going 😕 Link to comment Share on other sites More sharing options...
[Me...] Posted August 6, 2019 Share Posted August 6, 2019 "I tried to do it your way and it says unable to calculate alignment' This is your problem. ^^^^^^ As Richard and I pointed out, if Calypso won't calculate a simple 3-2-1 alignment on this part then that's where you need to start looking. There's no reason I can think of that Calypso is able to calculate an alignment with 3 planes but won't calculate a simple 3-2-1 alignment on the same part. There's also no reason I can think of as to why the machine is driving to the wrong location, regardless of the Z error your seeing. All of those symptoms point to a bad Base Alignment. Without seeing your alignment and the features being used I can't help you further. Robert Link to comment Share on other sites More sharing options...
[Da...] Posted April 29, 2020 Share Posted April 29, 2020 What is your Z values on the lower XYZ of the joystick box? If the Z with no probe is 0.7 to 0.9 you have a broken XXT head. Someone crashed it in Z and broke one of the two C plates in the head. Link to comment Share on other sites More sharing options...
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