#31
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This seems like a continuation of the problems you've had in the past (posts 269 and 303 of your thread) just not as pronounced.
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#32
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On second thought, I don't see how marks like those could be the result of runout in the router spindle. Spindle runout would leave a rough random cut on the edge. The edges of your board appear more like facets.
It has to be something other than that. Gerald and Mike and some other guys talked about improving your resolution. Changing to smaller pinions will be cheaper than buying a Smoothstepper and it will improve your resolution. Last edited by Doug_Ford; Sat 05 September 2009 at 14:27.. |
#33
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It could be interesting to try another PC.
And then we must not forget that this particular pattern, which has ovals and uneven curves, might be built up from small irregular bits of data. . . . . |
#34
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Gerald,
I have reached a new level of frustration with my ability to fix my problem and I am about ready to order new C Channel and start over on the table. On Saturday, I did listen to your words and I checked the V Wheels on the Gantry and I discovered that the wheels on the left side or 0,60 did not ride exactly on center. I added a .5mm washer to both the front and back. Once I did that, all wheels made excellent contact with the rails. I checked the wheels along the full length of the rails and it all looked good. I reinstalled the motors and moved the machine to its sleeping spot but I did not cut any thing. Sunday, I took a beach day. Today, I went out to test my efforts. The first thing that happened was the noise that came from the pinon gears and rack. I did not hear any noise on Saturday. So I got out the washer that I used to leve the motors to match the rack. Problem I described in another thread. After inserting the washers, the noise went away. I got some solid surface material and cut a diamond pattern at 70 IPM. The chatter was back. I then checked the Z Slide but it was good. I am open to suggestions and thanks for your help. |
#35
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Gerald has been able to successfully diagnose every problem everyone has had so far. The last thing he recommended was to try another PC so that's what I would do.
Last edited by Doug_Ford; Tue 08 September 2009 at 07:42.. |
#36
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Doug,
I would like to be able to try another computer but I don't have one and I don't know of any one that has one I can use. I did run the Mach test program and it checks out okay. I am willing to try any thing to resolve my problem and I appreciate all the help. |
#37
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Nils,
Do you access the Internet from a different PC than the one used for the MM? If so, just for a test, use the PC in the house to run Mach. |
#38
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Greg J,
The only other PC I have is a notebook computer which will not work. Thanks for the suggestion. |
#39
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Nils,
I bought a used Small Form Factor PC from these guys. It came with XP Pro and was ready to run. In addition to the price of the machine I paid shipping and taxes (they are located in Texas) for a total of $114. It arrived a couple of days after I placed the order. The computer is shown in this post from my build thread. I hope you are able to solve the problem soon. |
#40
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John
Thanks for the info but I have a cheap Pentinum III which I paid about the same. We are not sure that is the problem. I have no need for an additional computer unless I it is the problem. |
#41
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Nils,
I wish I was closer to you, I have a few you could try. I seem to keep getting older computers when I help a friend upgrade. |
#42
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Let me explain my frustration.
I am frustrated with me. I have reached the max of my mechanical ability. I am actually lost to some extent. When it comes to software and computers, I have some ability. I have the greatest respect for Gerald's design and abilities to resolve problems that people have with their builds and I did not mean I was frustrated with Gerald. I also have respect for the other bulders on this forum and their abilities. What I have done so far: 1) I have lubicated the X and Y Rails using Dupont's Teflon Dry Wax lubicant. 2) I have add some half washers to the motor mounts to make the pinon gears perpendicular to the rack. When I mean half washer here, I am talking about a washer that is cut in half. I am thinking of making some thing better. 3) I have rechecked that the Z Slide is perpendicular and the router bracked is level. When I cut flat things are good. 4) I did check the pinon gears for wear and it does not look like to me that there is a wear problem. I also checked to see if the pinon gear was bottoming out on the rack and it is not doing that. 5) How do I change the resolution? What resolution are you talking about? 6) How do I check for backlash with my geared motors? I went back over this thread to check all the suggestions, I hope I have answered them all or have requested additional clarification. I am still geting chatter when I cut at 70 IPM. Before I added the washer to the gantry wheels, my cuts were better but I had chatter. I don't know what to try next. Thank you for your assistance. Last edited by sailfl; Wed 09 September 2009 at 09:19.. |
#43
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Nils,
I am by no means an expert on the Mechmate, but I've spent a lot of my life building, troubleshooting and repairing machinery. I have followed your post and I have thought that what I would do is make some longish angled cuts in the same piece of stock with varying degrees on the angle. Perhaps you could start with a straight 'X' axis cut and then make subsequently steeper cuts in 10 degree increments until you reach a straight 'Y' axis cut. This would allow you to examine, compare and contrast the quality of the cuts under differing angles using a known straight vector. You also may want to try this twice. Once climb milling and once conventional milling. Just a thought. Regards, Jeff |
#44
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Jeff,
You beat me to it. I was also going to suggest the angled cuts. However, I would like to add an explanation as to why Nils should try this technique. There are a lot of us that think this is a resolution problem. Nils, since you seem to have a regular pattern, when you change the angle of the cut, depending on whether the angle is shallower or steeper, the regular pattern should lengthen or shorten. In my opinion, this will provide additional evidence that it is a resolution problem. You asked about resolution. A short answer is your gear box ratio. You said you know about computers. Imagine a couple of curves. One curve is analog and the other is digital. The analog curve is perfectly smooth but the digital curve is composed of a series of short lines and is sort of choppy like the picture Gerald drew. If you increase your resolution by changing your gearbox from 3.6:1 to 7.2:1 or to 14.4:1, you will have a smoother curve. One of the cheapest ways to change the ratio is to use a smaller pinion gear. |
#45
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Oh yeah. You can check the backlash in your gear box with a dial test indicator. Google it and I'll bet you find pictures of the set up. Harbor Freight has cheap dial indicators.
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#46
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Nils, when I looked at your .dxf file of the diagonal in question, it appeared to be a pure 45 degree line......is that correct?
Everyone else, are any of you having issues with 45 degree diagonals? I assume not. One of the factors that can make such a stark difference between similar machines is the performance of the PC. But Nils does not have a spare PC to test with. However, you could try something else........... A 45 degree diagonal means the pulse rates of X and Y are identical. For a test, program your Mach to cut a straight line at 50 IPM in the X direction. But, disconnect your y-gecko's inputs from the PMDX and connect it in parallel to one of the x-gecko's inputs. The machine will run at 70IPM on the diagonal, but Mach3 will not have the duty of synchronising the two axes. |
#47
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For experimental purposes, you can eliminate backlash by pushing against your y-car & gantry while it is cutting.
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#48
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Gerald,
Thanks for the suggestion. Just so I don't screw things up. I want to disconnect the three Y wires at the PMDX and connect them to the same connectors that the X wires are connected. I am working on trying to find a PC that I can borrow. |
#49
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Best to "park" the y-car away from the end of the gantry before swopping wires - you don't know for sure which way it will go...
You only need to move the "step" and "dir" wires onto the wires going to a x-gecko next to it (I assume they are G203V's). Leave "the" com where it is. |
#50
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Good thing I asked.
Could there be a problem with the ribbon cable that runs from the bottom of the Controller Box to the top where the PMDX is located? The ribbon cable is taped to the side of the box. |
#51
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Gerald,
I could not use the cables that run to the Gecko. They are too short so I attached a small wire and ran that to the X. It did not like it at all. The X with the new input did not like it at all. I also recalculated the steps for motor tuning. 30 pinons : 1.5 X Pi = 4.7124 2000 X 7.2 = 14,400 14,400 / 4.7124 = 3055.7677. The old setting was 3057. some thing |
#52
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I have verified that the ribbon cable is not a problem. I had a regular printer cable so I bypassed the ribbon cable the problem is still there.
I will have to put a file together to try Doug changing diagonal cuts. I am still thinking of people that might have a computer I can borrow to do a test. |
#53
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Hey Nils,
From a trouble shooting point of view, frustration is the worst kind of mind set. I can't count the number of times when I'm trying to solve a problem (with the MM also) and I'm pissed. I do more damage than good. The answer to the problem is staring you in the face and you can't see it for the blinders. I'm always amazed when I put it away for the evening and return the next morning (or whenever) how easy the problem is to see. Anyways, don't forget to take a break and clear the head. Now, if you have a project and customer is chomping at the bit, that's different. You'll figure it out. |
#54
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Nils, I am going to back away from this thread. I find it very frustrating to try and work with you. Example: In post #49 I ask you to test something. 20 minutes later you are onto a different course. An hour later you tell me that you have discarded my test, and that you are onto yet another course.
Helping people to build and run MechMates is not my profession, it is my hobby. Right now that hobby is too demanding and I am pushing the heavy aspects of it onto the backburner. |
#55
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Gerald,
I am sorry you feel that way. I have ADHD. So that is the way I operate. I jump from one thing to another. It frustrating for me also. I did not reject your test. I did try it but it appeared one x motor ran one way and the other ran the opposite direction. That was after I attached the Y Dir and Step into the X with the X still connected. I was concerned that I would damage some thing if I continued to try. So I reported back and in the mean time I tried some thing else. Maybe I did not set the test up correctly. Thank you for your time. |
#56
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Nils, tome precauciones antes de actuar con la electrónica.
Las recomendaciones son buenas. Sigo este hilo con atención. Me interesan mucho sus pruebas y los resultados obtenidos. Gracias. The mechanics of your machine seems perfect. You can put one fine ballpen in the router site and trace some diagonal and circular lines in different places of the table for see the accuracy. |
#57
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Good idea Ros.
Nils, if you move the car into the middle of the table with the Z axis all the way up, you shouldn't damage anything during Gerald's recommended test. Just don't cut anything at first. This step is just to confirm that things are working correctly before you try cutting. So the first step is to move the car into the middle of your table, place the Z axis all the way up, then connect the wires like Gerald told you too. When you use the keys on your keyboard to move the X Axis in any direction, you shouldn't hit a stop for a few seconds. A few seconds will be enough time to react and remove your finger from the button. With the wires connected per Gerald's instructions, the cutting bit should move on a diagonal when you press the X Axis button. In your last post, you wrote that the motors seemed to turn in opposite directions. Yep. The X axis motors have to since they face in opposite directions on the gantry. That's why you want to put the car in the middle of the table. Like Gerald said, you don't know which way it will move. (You could figure it out but putting the car in the middle of the table is much simpler.) Okay, back to the test. Once you have confirmed that your X and Y axes are moving together, program your Mechmate to cut a straight line on the X Axis. It will make a diagonal cut. If the cut is smooth, this would seem to indicate that changing the computer might fix your problem. If you get the same pattern as before, this would indicate that changing the resolution might help. I agree with Greg J too. It seems the more pissed off I get about a problem, the harder it is to solve. Relax and have a barley sandwich like Greg. |
#58
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Doug,
Doug thanks for helping. This AM, I went back out and tried again. I thought that maybe I had a bad connection. So I reconnected things again according to the what I understand. What I understand is this: Take the Dir and Step wires from the Y Gecko and connect them to one of the X Gecko Dir and Step. I left the X wires there that are already connected. So I had the X and the Y Dir and Step wires in the same X Gecko. I was not clear. Things don't move too well. It appears that the one of the gantry with only X is moving in the positive X direction and the other end of the gantry is moving in the negative X direction. They are in conflect. It doesn't make sense to me but it does not work the way it should. Because there is a conflict, I don't keep it running. I stop it. "connect it in parallel to one of the x-gecko's inputs" I guess I don't understand what this means. I think I am making the connection incorrectly. Send me you phone number by PM. May be you can walk me though it. Thanks |
#59
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Nils,
Actually you need to move the connections for the Y motor at the pmdx. You want to put it in paralell with one of the x motors pmdx outputs. This way, you are driving the y motor with the same signal as one of your x motors. The connections at the geckos remains untouched. You will have one pmdx output open and one x motor pmdx ouput coneected to one x gecko and one y gecko. The other x pmdx output remains as you had it. Hope this helps. Also see my pm. |
#60
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Heath,
Thanks, that is what I was going to do the first time but I misread Gerald's and thought I needed to do it at the Gecko's. Thanks |
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