Ebay SINTRON Kossel Mini full kit

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ohfurryone
However when auto-calibrating from pronterface it begins by probing the middle of the bed then twice in one spot near Z tower, then drives itself into the bed. I've already tried inverting all of the endstop logic settings but nothing works.

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ohfurryone
Hello everyone, I'm new to the forums here.

I recently brought a Sintron Kossel kit last week to see if it would be any good for what I need and I have spent since then trying to calibrate the printer.

I've so far read 8 tutorials and I believe I have set everything correctly, all the measurements are correct. However when auto-calibrating from pronterface it begins by probing the middle of the bed then twice in one spot near Z tower, then drives itself into the bed. I've already tried inverting all of the endstop logic settings but nothing works.

Perhaps someone knows what I'm doing wrong or perhaps maybe someone can upload a recent working version of the firmware? Any help would be appreciated, thanks.

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ohfurryone
I was trying to use Marlin master instead of 1.04, however using 1.04 doesn't seem to help. It probes each place randomly 3-10 times along the X axis only moving on the Y axis once, then hits the bed after 30-40 probes. The steppers seem to be wired correctly as the printer homes fine.

Trying to dry-print a test cube (with 1.04) results in the X tower plowing it's carriage into the base, the other two towers stop at what appears to be half way.

There doesn't seem to be an option for Z_RAISE_BEFORE_PROBING in this firmware version, although it does raise a little before probing each time. I set the probe retraction end points to Z levels 20 then 40 but it still hits the bed after it's weird erratic probing dance.

I measured the offsets from the picture somewhere in this topic as opposed to Sintrons manual. I've uploaded my configuration.h file to see if anyone can see anything wrong as I am at a loss for what to do.

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dc42
By default, the firmware will let you go down to -0.5mm on a delta.

If after auto calibration the heights are inconsistent, that probably means that you have an inconsistent trigger height for the IR sensor. This can be caused by the bed surface not being sufficiently uniform, but on a delta printer a common cause is that the effector is tilting slightly as it translates in the XY plane. Because the sensor is offset from the nozzle, this causes the relative heights of the nozzle and sensor to change.

To verify that this is what is happening, lower the nozzle so that it is just touching the bed, then use feeler gauges to measure the height of the bottom edge of the sensor board above the bed. Repeat at different probe points.

To minimise the effect of tilt on the trigger height, place the sensor as close to the nozzle as you reasonably can.

If tilt is causing trigger height differences as great as 1mm, then you have a lot of it and you need to improve your build. Here are some common causes of varying effector tilt:

1. Diagonal rods in a parallel pair are not quite the same length. If you can discern any difference sin the length of the rods, you can sort them into length order and then pair them, so that the rods in each pair are as close to equal lengths as possible. Or make new rods, using a jig to get them all the same length.

2. The bearing spacing is not quite the same at the top of a pair of parallel rods as it is at the bottom. Depending on the design, you may be able to use shims or washers under some of the joints to equalise the spacing.

3. The lines between the pairs of bearings on the 3 carriages do not intersect at 120 degree angles (or the bearing lines on the effector are not at 120 degree angles, but that is less likely). I had that problem because I had one extra 0.5mm washer between a carriage and one of its three wheels. It caused a height variation of about 0.25mm.

4. The carriages are rotating as they move up and down, because the wheels or linear sliders are too loose.

Once you have reduced the trigger height differences to reasonable proportions, you can correct for the differences using the H parameter on the G30 commands in bed.g. You don't need to print a calibration piece, that is for orthogonal axis correction.

HTH David

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ohfurryone
I was trying to use Marlin master instead of 1.04, however using 1.04 doesn't seem to help. It probes each place randomly 3-10 times along the X axis only moving on the Y axis once, then hits the bed after 30-40 probes. The steppers seem to be wired correctly as the printer homes fine.

Trying to dry-print a test cube (with 1.04) results in the X tower plowing it's carriage into the base, the other two towers stop at what appears to be half way.

There doesn't seem to be an option for Z_RAISE_BEFORE_PROBING in this firmware version, although it does raise a little before probing each time. I set the probe retraction end points to Z levels 20 then 40 but it still hits the bed after it's weird erratic probing dance.

I measured the offsets from the picture somewhere in this topic as opposed to Sintrons manual. I've uploaded my configuration.h file to see if anyone can see anything wrong as I am at a loss for what to do.

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hacker

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DRTak
Way back I 3d printed the circular Mercedes sign calibration part. Then laser printed the matching *.pdf. It said impossibly that x tower was 120 deg y tower was 121deg and 120 deg on z tower. For a total of 361 deg. So if my build is not true 120 deg from each other will this be causing these errors. How can I double check ? Or fix it?

I don't think it could possibly say that. It doesn't say anything about Z-tower, you're supposed to align the object so that Z-tower is zero degrees and then if one is 120 and the other is 121, then the third angle is 119. That object/pdf give you basically the angles between Z and X and Z and Y.

Anyway, I've had similar problem with one part of the bed being somewhat (not as bad as your case) lower than the other and so I suspected tilt — I've redone rods, but if my hands were so reliable I wouldn't need 3d printer! So I suspect its rods. Though David's list of things to check is really precious piece of advice I still need to follow.

Meanwhile, what I've done now is I've calibrated, then went to all the points equipped with the sheet of paper and based on the difference added H to each bed.g's point. And it looks like it did help! Maybe David can comment whether the procedure is sane and useful for others or it has just helped me because of sheer luck ;-)

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DRTak

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hacker

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DRTak
Way back I 3d printed the circular Mercedes sign calibration part. Then laser printed the matching *.pdf. It said impossibly that x tower was 120 deg y tower was 121deg and 120 deg on z tower. For a total of 361 deg. So if my build is not true 120 deg from each other will this be causing these errors. How can I double check ? Or fix it?

I don't think it could possibly say that. It doesn't say anything about Z-tower, you're supposed to align the object so that Z-tower is zero degrees and then if one is 120 and the other is 121, then the third angle is 119. That object/pdf give you basically the angles between Z and X and Z and Y.

Anyway, I've had similar problem with one part of the bed being somewhat (not as bad as your case) lower than the other and so I suspected tilt — I've redone rods, but if my hands were so reliable I wouldn't need 3d printer! So I suspect its rods. Though David's list of things to check is really precious piece of advice I still need to follow.

Meanwhile, what I've done now is I've calibrated, then went to all the points equipped with the sheet of paper and based on the difference added H to each bed.g's point. And it looks like it did help! Maybe David can comment whether the procedure is sane and useful for others or it has just helped me because of sheer luck ;-)

Hacker,
I did change the bed.g file to add the H paramenter. But it didnt work. I assume I did it wrong. Can u give me an example of what the G30 code looks like with an H parameter in it?

Right now for example the center of my bed is always off by -.2 after auto calibration. My z tower is off by -.25. I just want it all to be 0. LOL. At least get my center of the bed zero. That would start things in the right direction

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DRTak
Hacker thanks for getting back to me. I got the center to be zero finally. I auto calibrated 4 times. Now it is zero. But the outer towers are still off. But at least they are off by the same amount roughly.

I got the numbers to be roughly the same by shutting the lights off in the room? I installed LED light bulbs and maybe thats the issue. So i just shut off the light in the room. Calibrated and it looks like the numbers are close every time. Even though they are not zero.

My H value is say -0.3. Thats because my Y tower is off by -.3. Meaning I have to push it down into the bed by -.3 to grip paper? So did I do it right?

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Rossini
does anyone know if the sintron extrusions are compatible with the robotdigg metal corners?

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MrPCatt
... the object cooler is connected to the default port on the ramps ( i think its c4?) [snip] But the fan obviously ignores it and gets full speed all the time when the printer gets power. Could somebody please give me a hint where to configure this? I think it should be in the firmware somewhere, but I cannot find anything related to this.

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dc42

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DRTak
Hacker thanks for getting back to me. I got the center to be zero finally. I auto calibrated 4 times. Now it is zero. But the outer towers are still off. But at least they are off by the same amount roughly.

I got the numbers to be roughly the same by shutting the lights off in the room? I installed LED light bulbs and maybe thats the issue. So i just shut off the light in the room. Calibrated and it looks like the numbers are close every time. Even though they are not zero.

My H value is say -0.3. Thats because my Y tower is off by -.3. Meaning I have to push it down into the bed by -.3 to grip paper? So did I do it right?

Sounds to me that you have the wrong sign for your H parameters. The principle is:

1. Measure the Z probe trigger height at each probe point. One way is to lower the head so that it just grips a piece of paper, send G92 Z0, raise the head 5mm, send G30 S-1, and read the height off the web interface or using M114.

2. Set the G31 trigger height to the trigger height you measured at the centre of the bed.

3. At the other probe points in bed.g, set the H parameter to the trigger height at that point minus the trigger height at bed centre.

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DRTak

I have been messing around with the H parameters all day long. I finally have it close enough. Not zero zero zero zero like I would like.

Nozzle is 0.35 above the bed after auto calibration (ie not zero)
X tower is -0.10
Y tower is -0.05
Z tower is -0.40

Now after I do multiple auto calibrations. Those numbers just rotate around. So The nozzle may be 0.05. The Y tower will be 0.35 etc. It is never just zero, zero, zero, and zero. Oh well

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Rossini
does anyone know if the sintron extrusions are compatible with the robotdigg metal corners?

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Sir_Death

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DRTak

I have been messing around with the H parameters all day long. I finally have it close enough. Not zero zero zero zero like I would like.

Nozzle is 0.35 above the bed after auto calibration (ie not zero)
X tower is -0.10
Y tower is -0.05
Z tower is -0.40

Now after I do multiple auto calibrations. Those numbers just rotate around. So The nozzle may be 0.05. The Y tower will be 0.35 etc. It is never just zero, zero, zero, and zero. Oh well

Sounds to me, your Endstops are not repeatable triggering at the exact same height - I have the same issue and I'm just waiting for Hall-Sensors to arrive http://notanumber.net/archives/66/upgrading-my-reprap-with-cheap-hall-effect-sensors

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dc42
Ordinary endstop microswitches are adequate if they are used correctly and they are of good quality. I suggest you do some tests to see what the repeatability is. Here is one such test:

1. Create a copy of your bed.g file, with S-1 on the last G30 command instead of S6 (assuming S6 is what you are using). Make sure it includes a G28 command near the beginning to home the printer before probing.

2. "Print" that file several times from the console in the web interface or from Pronterface. Each time, it will display the probe error at each point. Are those errors consistent?

btw if you are adjusting travel speeds, the travel speed between probe points is set by the T parameter in the M558 command in config.g.

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dc42
Something is not right. You have some very large probe errors there. In particular, you have a large jump from -2.8mm to +2.07mm at points P3 and P4, that I presume are adjacent. What are the coordinates of P3 and P4? Does the nozzle height really change by nearly 5mm when the head moves between those points?


I don't know where your probe points are, but I fed the height errors into my calibration calculator at [escher3d.com] using the suggested 10 probe points, and it suggested adjustments that reduce the deviation to 0.84mm - which is still very large, but better.

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dc42
Something is not right. You have some very large probe errors there. In particular, you have a large jump from -2.8mm to +2.07mm at points P3 and P4, that I presume are adjacent. What are the coordinates of P3 and P4? Does the nozzle height really change by nearly 5mm when the head moves between those points?


I don't know where your probe points are, but I fed the height errors into my calibration calculator at [escher3d.com] using the suggested 10 probe points, and it suggested adjustments that reduce the deviation to 0.84mm - which is still very large, but better.

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DRTak

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dc42
Something is not right. You have some very large probe errors there. In particular, you have a large jump from -2.8mm to +2.07mm at points P3 and P4, that I presume are adjacent. What are the coordinates of P3 and P4? Does the nozzle height really change by nearly 5mm when the head moves between those points?


I don't know where your probe points are, but I fed the height errors into my calibration calculator at [escher3d.com] using the suggested 10 probe points, and it suggested adjustments that reduce the deviation to 0.84mm - which is still very large, but better.

At the Y and Z tower. The nozzle is way off. I didnt exactly measure the difference but it might be around 5mm Z height off. I am not using a glass bed. I am using the original Sintron Heatbed made of aluminum.

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dc42

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DRTak

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dc42
Something is not right. You have some very large probe errors there. In particular, you have a large jump from -2.8mm to +2.07mm at points P3 and P4, that I presume are adjacent. What are the coordinates of P3 and P4? Does the nozzle height really change by nearly 5mm when the head moves between those points?


I don't know where your probe points are, but I fed the height errors into my calibration calculator at [escher3d.com] using the suggested 10 probe points, and it suggested adjustments that reduce the deviation to 0.84mm - which is still very large, but better.

At the Y and Z tower. The nozzle is way off. I didnt exactly measure the difference but it might be around 5mm Z height off. I am not using a glass bed. I am using the original Sintron Heatbed made of aluminum.

Are you trying to use my IR sensor with a bright aluminium target? If so, it won't give accurate results. The aluminium reflects light too strongly and saturates the sensor, and small scratches have a big effect. You can tell this is happening because the Z probe reading will be greater than 1000, instead of about 465 just before triggering and about 535 after.

So I suggest you do one of the following:

1. Use a different bed surface. One possibility would be to put BuildTak on top of your aluminium. Another would be to paint the aluminium black and put glass on top of it. A third is to put PEI sheet painted black underneath on top (see my blog). Or you may find that putting Kapton tape on top is enough.

2. Use a different type of Z probe. An inductive sensor will work against aluminium without glass on top, but will be larger than the IR probe.

3. Don't use a Z probe at all. Measure the nozzle height error at each probe point. Then either enter the figures into my online calculator, or into the bed.g file. If putting them into the bed.g file, put them as the Z parameters of the probe points instead of Z-99999 on the G30 commands.