Problems with glass plate on Printrbot Simple Metal

Problems with glass plate on Printrbot Simple Metal

Postby paynterf » 2015-Nov-Sun-16-Nov

I have been having problems with what I believe to be a slightly warped print bed on my Simple Metal, so I decided to try adding a glass plate, with copper foil patches placed on top of the glass to trigger the Z-axis probe.

The copper foil patches seem to trigger the Z-axis probe properly, so I thought I was home free. However, when I tried some test prints I found I had to significantly change the Z-axis offset (M212 commandI) to get decent first-layer adhesion, depending on where the print was located on the bed. If the print location was near the X/Y home position, then a Z-axis offset of -0.7 seemed to work great, but printing that same item in the far right corner required a Z offset of -2.0 - MUCH bigger than I had ever had to use with the original print bed.

Also, If I left the Z-axis offset at -2.0 (for a print in the far right corner) and then tried to print the same item near the X/Y home point, the extrusion head started cutting into the painters tape - badly!

Based on the above results, it seems the glass plate setup is tilted DOWNWARD for increasing X & Y, but I'm not sure why the 'auto-levelling' (actually more like 'software tilt correction') isn't compensating properly for this.

Moreover, when I moved the bed/print-head around manually, I got exactly the opposite results. When I moved the bed to the left (i.e. increasing X, I think) and/or the Y-arm toward the front, the print head started to score the painters tape. This implies that the print bed is sloped UPWARD for increasing X & Y.

I haven't been tracking these numbers, so I don't know if the difference between 0.88 at (10,143) vs 1.98 at (10,10) and (143,10) is significant or not


So basically, I'm completely baffled by what's going on here. I wrote all this up in a post with photos on my "Paynters Palace" blog (apparently as a new poster I can't post the URL, so please search for 'glass-print-bed-for-printrbot-simple-metal'). If anyone has a clue as to what is happening, I'd love to hear it. In the meantime, I guess I'll go back to printing on my original print bed, warps and all ;-).

Frank


Added Note: I went back and looked at the probe results from the last print attempt (the one that ran the extruder tip into the painter's tape).
14:38:46.107 : Bed x: 10 y: 143.00 z: 0.88
14:38:49.927 : Bed x: 10 y: 10 z: 1.91
14:38:53.989 : Bed x: 143.00 y: 10 z: 1.98
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Problems with glass plate on Printrbot Simple Metal

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Re: Problems with glass plate on Printrbot Simple Metal

Postby bbrown64 » 2015-Nov-Mon-08-Nov

I read someplace that when using a glass bed the "metal" that triggers the Z-Probe should be under the glass. I also read that a piece of thin galvanized sheetmetal cut the same size as the glass plate works well. Putting small tabs on the plate just to trigger the Z-Probe in certain places may not be the correct thing to do. The printer prints all over the bed so it should read all over the bed.
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Re: Problems with glass plate on Printrbot Simple Metal

Postby RetireeJay » 2015-Nov-Mon-09-Nov

BBrown, sorry to contradict, but...

(Speaking from a position of partial ignorance here, because I don't have a probe) I must say that I have definitely read about putting tabs of metal ON TOP of the glass for the very reason that the thickness of the glass prevents correct operation of the probe. That is, the probe can't see metal that far away, so it doesn't work when trying to "look through" glass.

And once the probe has checked its three points (using the G29 command) then it has finished its work. The probe itself is not being used at all during the print; only the data that it generated is being used. The three-point check "maps" a plane which the software then uses to "correct" the Z height all over the bed. So it's definitely not necessary to have the probe be "usable" anywhere except the three specific points where it does its checking.

I'm wondering if the Original Post problem has to do with the setup of the "Home" position and the location of Zero. Some Printrbots "home" to X = 0, Y = Max whereas others "home" to X = 0, Y = 0. If there is a mismatch between how the printer is homing and how the G29 zeroing is being performed, then maybe there could be a problem like the one observed, where the "correction" seems to be acting opposite to the desired effect. I'd say to review very carefully which direction Y moves when you give it a manual command to move in the positive direction, and where it "homes" to to make sure that your bot is set up consistently.
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Re: Problems with glass plate on Printrbot Simple Metal

Postby veng » 2015-Nov-Mon-10-Nov

The probe on my Simple Metal works very well, so I decided to add one to my MendelMax which has a glass bed followed with an aluminum heat spreader, then a thin cork insulator and finally the Al mounting plate. Because of the problems caused by glass, I chose a capacitive sensor. Because of the level shift issues, I used an NPN output, so this is not an apples to apples discussion of a Printrbot sensor. The sensor is being run at 5V which also may be an issue.

I found with strong enough Bulldog clips that the glass was bent. Clearly visible with a straight edge. Removing the clips and taping the glass fixed that but the take away is glass can be quite flexible.

After that, I ran statistics and found that the repeatability of the sensor is poor, specifically the standard deviatilon is too high. My best guess is that the spacing between the glass and aluminum varies and causes the capacitance to vary. Thus, I'd guess that neither a capacitive or inductive sensor will work alone, maybe tape in the corners will allow tramming.

However, I DO want to be able to measure over the entire bed as I know it is not guaranteed flat. Next I'll probably try dc42's optical sensor as it wiil work with any bed.

I'm also testing accelerometers as that should sense X. Y, Z limits and home positions possibly also allow direct motor tuning by sensing when the motors can't keep up. So far the first sensor will require more signal processing to eliminate the noise as I can't distinguish between tapping the bed and variations in motor movements.
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Re: Problems with glass plate on Printrbot Simple Metal

Postby Some Printr Noob » 2015-Nov-Mon-22-Nov

I have put aluminum tape under glass, and then have it all on top of a heated build plate. Glass is relatively thin at 2.5mm, but my probe does sense it. You'll probably have to adjust your Z axis offset to account for the glass though.
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Re: Problems with glass plate on Printrbot Simple Metal

Postby thawkins » 2015-Nov-Tue-03-Nov

Some Printr Noob wrote:I have put aluminum tape under glass, and then have it all on top of a heated build plate. Glass is relatively thin at 2.5mm, but my probe does sense it. You'll probably have to adjust your Z axis offset to account for the glass though.


The issue with sensing a metal plate under the glass, is

1. It assumes that the gap between the plate and the glass is constant and that the plate is not warped.
2. the gap may change with pressure/weight on the glass.

Tape under the glass is probably OK as long as it is actually attached to the back of the glass.
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Re: Problems with glass plate on Printrbot Simple Metal

Postby paynterf » 2015-Nov-Wed-14-Nov

I'm wondering if the Original Post problem has to do with the setup of the "Home" position and the location of Zero. Some Printrbots "home" to X = 0, Y = Max whereas others "home" to X = 0, Y = 0. If there is a mismatch between how the printer is homing and how the G29 zeroing is being performed, then maybe there could be a problem like the one observed, where the "correction" seems to be acting opposite to the desired effect. I'd say to review very carefully which direction Y moves when you give it a manual command to move in the positive direction, and where it "homes" to to make sure that your bot is set up consistently.


Interesting point, but that would imply that the correction has ALWAYS been wrong, as I haven't changed the algorithm, just the bed height.

From my original post:
14:38:46.107 : Bed x: 10 y: 143.00 z: 0.88
14:38:49.927 : Bed x: 10 y: 10 z: 1.91
14:38:53.989 : Bed x: 143.00 y: 10 z: 1.98

So my Printrbot Simple Metal 'homes' to X = 0, Y = MAX, then checks X = 10, Y = MAX, X = 10, Y = 10, X = MAX, Y = 10 in that order.

Regarding the suggestion that maybe the glass plate itself is warped due to the clamping force of the binder clips holding it to the print bed: I checked this with a good straight edge, and AFAICT, it is VERY flat. I couldn't see any light at all under the straight edge, and a piece of printer paper (0.08mm) would not slide freely under the edge at any point. I checked for flatness in both X & Y directions as well as diagonally. If there's any warping, I can't find it :-(.

As a thought, does anyone know how I can manually command a 'auto-level' sequence? If I can do that, I can check multiple points on the plate by changing the bed dimension in Repetier's config page - just a thought.

Frank
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Re: Problems with glass plate on Printrbot Simple Metal

Postby Some Printr Noob » 2015-Nov-Wed-18-Nov

Send a G29 command to the printer? That should do it.

I have my aluminum tape attached to the underside of the glass, fyi.
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Re: Problems with glass plate on Printrbot Simple Metal

Postby paynterf » 2015-Nov-Fri-21-Nov

I have just completed what I think is a pretty thorough investigation into this problem, and have posted all the gory details on my blog site 'Paynters Palace' http://fpaynter.com/category/3d-printing/printrbot/. You can view the article there by selecting the '3D Printing' menu item and looking for the "glass-print-be-metal-part-ii" article

The bottom line appears to be that the vaunted Printrbot tilt correction feature isn't working very well (or at all), at least for my Printrbot Simple Metal :-(

Any thoughts and/or suggestions?

TIA,

Frank

PS - what's the deal with not being able to include off-site URL's? That seems unnecessarily harsh, and I'm sure no one here wants me to directly include the huge number of images and charts associated with the article ;-).
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Re: Problems with glass plate on Printrbot Simple Metal

Postby RetireeJay » 2015-Nov-Fri-22-Nov

You will be able to post off-site URL's after you have racked up a certain number of posts on the forum. It's not a huge number, but it helps keep spammers at bay. You wouldn't believe how many people (or robots) try to spam the forum. I'll fix the link for you.
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Re: Problems with glass plate on Printrbot Simple Metal

Postby paynterf » 2015-Nov-Sat-07-Nov

RetireeJay wrote:You will be able to post off-site URL's after you have racked up a certain number of posts on the forum. It's not a huge number, but it helps keep spammers at bay. You wouldn't believe how many people (or robots) try to spam the forum. I'll fix the link for you.



Thanks!!

Frank
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Re: Problems with glass plate on Printrbot Simple Metal

Postby paynterf » 2015-Nov-Tue-22-Nov

paynterf wrote:I have just completed what I think is a pretty thorough investigation into this problem, and have posted all the gory details on my blog site 'Paynters Palace' http://fpaynter.com/category/3d-printing/printrbot/. You can view the article there by selecting the '3D Printing' menu item and looking for the "glass-print-be-metal-part-ii" article

The bottom line appears to be that the vaunted Printrbot tilt correction feature isn't working very well (or at all), at least for my Printrbot Simple Metal :-(

Any thoughts and/or suggestions?

TIA,

Frank

PS - what's the deal with not being able to include off-site URL's? That seems unnecessarily harsh, and I'm sure no one here wants me to directly include the huge number of images and charts associated with the article ;-).


Well, I have just spent an entire evening struggling with my Printrbot Simple Metal and my glass plate addition, trying to get consistent print results across the entire print bed. I ran a number of experiments where I printed the first few layers of a 20mm cal cube at 5 different positions on the print bed, hoping to figure out what adjustments, if any, were required to get consistently good prints. After several hours of testing, I wound up more confused than when I started, but miraculously (and I can't think of a better adverb than that) with a configuration that seems to print well - no thanks to anything deliberate on my part!

AFAICT at this point, I am convinced that the Printrbot tilt-correction feature does work, although exactly how I'm at a loss to say. For a while I thought the problems I was having might be related to some sort of coupling between incorrect print bed dimension values in Repetier somehow getting fed into Printrbot's tilt correction calculations, but futher testing seems to have disproved that. When I started, I could consistently get good prints at the left rear edge (10,150), and bad prints at the right near edge (150,0). After going through LOTS of tests with different shim combinations, I wound up back in the same (no shim) configuration, except now I'm getting consistently good prints at all positions - go figure. All the gory details plus photos are on my blog site 'Paynters Palace' at http://fpaynter.com/2015/11/glass-print ... -part-iii/


My Simple Metal is about a year old now, and I have never updated the firmware. I'm now wondering if there have been some changes/bugfixes to this algorithm since I got my unit. Does anyone have any specific knowledge about the Printrbot tilt correction algorithm, including any updates and/or revisions to same over time? Any Printrbot folks on this forum?

TIA,

Frank
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Re: Problems with glass plate on Printrbot Simple Metal

Postby thawkins » 2015-Nov-Wed-04-Nov

paynterf wrote:
paynterf wrote:I have just completed what I think is a pretty thorough investigation into this problem, and have posted all the gory details on my blog site 'Paynters Palace' http://fpaynter.com/category/3d-printing/printrbot/. You can view the article there by selecting the '3D Printing' menu item and looking for the "glass-print-be-metal-part-ii" article

The bottom line appears to be that the vaunted Printrbot tilt correction feature isn't working very well (or at all), at least for my Printrbot Simple Metal :-(

Any thoughts and/or suggestions?

TIA,

Frank

PS - what's the deal with not being able to include off-site URL's? That seems unnecessarily harsh, and I'm sure no one here wants me to directly include the huge number of images and charts associated with the article ;-).


Well, I have just spent an entire evening struggling with my Printrbot Simple Metal and my glass plate addition, trying to get consistent print results across the entire print bed. I ran a number of experiments where I printed the first few layers of a 20mm cal cube at 5 different positions on the print bed, hoping to figure out what adjustments, if any, were required to get consistently good prints. After several hours of testing, I wound up more confused than when I started, but miraculously (and I can't think of a better adverb than that) with a configuration that seems to print well - no thanks to anything deliberate on my part!

AFAICT at this point, I am convinced that the Printrbot tilt-correction feature does work, although exactly how I'm at a loss to say. For a while I thought the problems I was having might be related to some sort of coupling between incorrect print bed dimension values in Repetier somehow getting fed into Printrbot's tilt correction calculations, but futher testing seems to have disproved that. When I started, I could consistently get good prints at the left rear edge (10,150), and bad prints at the right near edge (150,0). After going through LOTS of tests with different shim combinations, I wound up back in the same (no shim) configuration, except now I'm getting consistently good prints at all positions - go figure. All the gory details plus photos are on my blog site 'Paynters Palace' at http://fpaynter.com/2015/11/glass-print ... -part-iii/


My Simple Metal is about a year old now, and I have never updated the firmware. I'm now wondering if there have been some changes/bugfixes to this algorithm since I got my unit. Does anyone have any specific knowledge about the Printrbot tilt correction algorithm, including any updates and/or revisions to same over time? Any Printrbot folks on this forum?

TIA,

Frank


Printrbot did not develop the automatic bed leveling feature, its a feature of "Marlin", which is the firmware they use. It was developed by a group of enthusiasts using tbe open source model.

The version of Marlin they ship is at least 18 months old, and yes there have been many changes since it has been forked away to the printrbot version. I gave up completly on autoleveling becuase of many if the reasons you have outlined.

I find that it is simpler, easier and better to manualy level the bed, and just use the sensor and the G28 command as a z height sensor, and not use G29 to create a correction map. The latest printer i have built does not have a probe at all and is far better for it. Just a simple z height end stop switch.
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Re: Problems with glass plate on Printrbot Simple Metal

Postby paynterf » 2015-Nov-Wed-09-Nov

thawkins wrote:
Printrbot did not develop the automatic bed leveling feature, its a feature of "Marlin", which is the firmware they use. It was developed by a group of enthusiasts using tbe open source model.

The version of Marlin they ship is at least 18 months old, and yes there have been many changes since it has been forked away to the printrbot version. I gave up completly on autoleveling becuase of many if the reasons you have outlined.

I find that it is simpler, easier and better to manualy level the bed, and just use the sensor and the G28 command as a z height sensor, and not use G29 to create a correction map. The latest printer i have built does not have a probe at all and is far better for it. Just a simple z height end stop switch.


Thanks for the background on the tilt correction feature - I didn't know that this pre-dated Printrbot. I guess I'm coming to the same conclusion as you - it doesn't seem to be worth the candle. Now that I have a really flat plate that works, and I know about the G28 and G30 (probe anywhere) commands, I'm pretty sure I can get my print bed level within a few tenths of a millimeter. Once this has been accomplished, the tilt correction feature isn't needed.

Any idea how to turn it OFF in the stock Printrbot firmware? Will I have to flash it with a modified version of Marlin to do this?

TIA,

Frank
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Re: Problems with glass plate on Printrbot Simple Metal

Postby paynterf » 2015-Nov-Wed-14-Nov

In the latest episode of my glass plate print bed saga, I decided to try and manually level the plate, thereby removing (as much as possible) the effect of the apparently ineffective and/or destructive Printrbot/Martin tilt correction scheme. I was able to (mostly) accomplish this, and I wrote up the results at http://fpaynter.com/2015/11/glass-print ... l-part-iv/

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Re: Problems with glass plate on Printrbot Simple Metal

Postby RetireeJay » 2015-Nov-Wed-14-Nov

So now that you have your bed level, just don't issue a G29 command at all. Instead, use G28 Z0. You may need to diddle with offsets somehow to get the right nozzle height. But then (hopefully) the Z axis worm gear won't move AT ALL during the printing of a given layer.
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Re: Problems with glass plate on Printrbot Simple Metal

Postby paynterf » 2015-Nov-Wed-15-Nov

RetireeJay wrote:So now that you have your bed level, just don't issue a G29 command at all. Instead, use G28 Z0. You may need to diddle with offsets somehow to get the right nozzle height. But then (hopefully) the Z axis worm gear won't move AT ALL during the printing of a given layer.



Yay - I'll try that tonight!!

Frank
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Re: Problems with glass plate on Printrbot Simple Metal

Postby paynterf » 2015-Nov-Wed-20-Nov

paynterf wrote:
RetireeJay wrote:So now that you have your bed level, just don't issue a G29 command at all. Instead, use G28 Z0. You may need to diddle with offsets somehow to get the right nozzle height. But then (hopefully) the Z axis worm gear won't move AT ALL during the printing of a given layer.



Yay - I'll try that tonight!!

Frank


RetireeJay - Thanks for the suggestion about omitting the G29 command. I did this, and got a pretty nice test print series, with absolutely no intra-layer Z-axis movement at all - very cool! I updated the post at http://fpaynter.com/2015/11/glass-print ... l-part-iv/ with a photo of the latest test series. In the future I'll use the G29 and G30 commands just for bed leveling support (they will provide the needed Z-axis probe numbers), but NOT for actual printing.

Thanks again!

Frank
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Re: Problems with glass plate on Printrbot Simple Metal

Postby Mooselake » 2015-Nov-Fri-12-Nov

Check out RJ's dial gauge adapter. It wasn't designed for a Simple but the concept will introduce you to the next level of alien probe free printing. I can adjust my plywood plus within the tolerance of my digital gauge.

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Re: Problems with glass plate on Printrbot Simple Metal

Postby paynterf » 2015-Nov-Fri-16-Nov

Mooselake wrote:Check out RJ's dial gauge adapter. It wasn't designed for a Simple but the concept will introduce you to the next level of alien probe free printing. I can adjust my plywood plus within the tolerance of my digital gauge.

Kirk


Hmm, dial gauge - good idea. Used to use those during my machine shop period. Shouldn't be a problem to print up an adapter for the current probe mount. McMaster-Carr here I come! ;-)

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Re: Problems with glass plate on Printrbot Simple Metal

Postby Mooselake » 2015-Dec-Sat-17-Dec

Harbor Freight (ohh, the horror) isn't a bad place to get dial gauges from - I have their digital version and it works quite well. Being a tool junkie I have several of the cheap mechanical versions (4 or 5, something like that, from several sources but mostly Enco), also. In this application you're interested in repeatability (zero being in the same place), not accuracy (1.000 mm reading 1.000 mm), so the cheap versions should be adequate. An article I read a while back did some comparison tests, and while the cheap gauges didn't handle the drop tests like the expensive ones their accuracy was pretty close. You're not looking for submicron precision here, hundredths of a mm are fine. Mine was adjustable to within the 0.01 tolerance of the HFD.

OTOH, nothing beats the nice feeling you get when holding your Mitutoyo :)

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Re: Problems with glass plate on Printrbot Simple Metal

Postby paynterf » 2015-Dec-Sun-20-Dec

Mooselake wrote:Harbor Freight (ohh, the horror) isn't a bad place to get dial gauges from - I have their digital version and it works quite well.

OTOH, nothing beats the nice feeling you get when holding your Mitutoyo :)

Kirk


Great idea - I'll be looking for one at my local Harbor Freight tomorrow. I did check McMaster-Carr, but was turned off by the prices.

FWIW, my glass plate manually leveled print bed is doing nicely now, but I'd love to literally 'dial it in' some more ;-).

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Re: Problems with glass plate on Printrbot Simple Metal

Postby paynterf » 2015-Dec-Tue-18-Dec

paynterf wrote:
Mooselake wrote:Harbor Freight (ohh, the horror) isn't a bad place to get dial gauges from - I have their digital version and it works quite well.

OTOH, nothing beats the nice feeling you get when holding your Mitutoyo :)

Kirk


Great idea - I'll be looking for one at my local Harbor Freight tomorrow. I did check McMaster-Carr, but was turned off by the prices.

FWIW, my glass plate manually leveled print bed is doing nicely now, but I'd love to literally 'dial it in' some more ;-).

Frank


So I finally got over to my local Harbor Freight and found a nice dial indicator for all of $16 (Item #623 if you are interested), and 'dialed in' my glass plate. When I was done, the plate was flat to within 0.1mm everywhere - neat!

Then I did some test prints and got pretty good results, so I *thought* I was all set.....

And then I screwed up - I pulled all the copper foil tape off the glass plate (thinking I didn't need that anymore as I wasn't using the Z-axis probe G29 command any more), and put it all back together, only to discover that the G28 command in the start script tries to drive the extruder through my glass plate - yikes!

So, can anyone tell me the right way to set up the start/stop/kill scripts, and how to achieve a consistent Z-axis 'home' position without using the Z-axis probe? I'm using Repetier Host as the controller, and AFAICT, all the Z-axis 'Home' button on RH does is reset the Z-axis position value to 0.00 without actually moving the Z-axis motor at all. Is there any way to tell my Printrbot/RH where Z=0 is *without* using the Z-axis probe?

TIA,

Frank
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Re: Problems with glass plate on Printrbot Simple Metal

Postby blort » 2015-Dec-Tue-18-Dec

a mechanical Z probe could do all you want. you want to be able to Z 0 detect without magnetic/inductive/capacitive dependency. there are mechanical Z probe adapters for the simple metal on thingiverse if I recall.

disclosure : I am not using a mechanical Z probe as I am on the stock heated/kapton solution and the work to use zebra/PEI/borosilicate just doesn't seem to be worth it to me right now since what I have is working. I still have my non-heated bed and would be happy to pass it on down the line if you PM me and we can work out the shipping. free to a good home, but I am not paying to get it to anyone :)
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Re: Problems with glass plate on Printrbot Simple Metal

Postby paynterf » 2015-Dec-Tue-22-Dec

blort wrote:a mechanical Z probe could do all you want. you want to be able to Z 0 detect without magnetic/inductive/capacitive dependency. there are mechanical Z probe adapters for the simple metal on thingiverse if I recall.

disclosure : I am not using a mechanical Z probe as I am on the stock heated/kapton solution and the work to use zebra/PEI/borosilicate just doesn't seem to be worth it to me right now since what I have is working. I still have my non-heated bed and would be happy to pass it on down the line if you PM me and we can work out the shipping. free to a good home, but I am not paying to get it to anyone :)


Thanks for the pointer on using a mechanical switch as a Z-axis probe replacement. I should be able to whip that up pretty quickly ;-).

Regards,

Frank
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Re: Problems with glass plate on Printrbot Simple Metal

Postby paynterf » 2015-Dec-Wed-21-Dec

paynterf wrote:
blort wrote:a mechanical Z probe could do all you want. you want to be able to Z 0 detect without magnetic/inductive/capacitive dependency. there are mechanical Z probe adapters for the simple metal on thingiverse if I recall.

disclosure : I am not using a mechanical Z probe as I am on the stock heated/kapton solution and the work to use zebra/PEI/borosilicate just doesn't seem to be worth it to me right now since what I have is working. I still have my non-heated bed and would be happy to pass it on down the line if you PM me and we can work out the shipping. free to a good home, but I am not paying to get it to anyone :)


Thanks for the pointer on using a mechanical switch as a Z-axis probe replacement. I should be able to whip that up pretty quickly ;-).

Regards,

Frank



While I was looking at mechanical stop switch mounting options and wondering if I have a Rev D or Ref F board (it makes a big difference in the wiring), it suddenly occurred to me that I already had a perfectly good Z-axis probe - it was just in the wrong place! If I simply relocated the metal-sensing probe so that it sensed the chassis rather than the print bed, I could still have my glass plate and not have to do any wiring at all - cool! So, after looking at the options, I finally decided to relocate the probe to the rear post of the vertical carriage, as shown in the attached image. I made up a simple bracket to hold the probe, and super-glued it to the carriage post. So far, this seems to work great!

Frank

151216 ZProbeReLo.jpg
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Re: Problems with glass plate on Printrbot Simple Metal

Postby blort » 2015-Dec-Wed-23-Dec

Clever!

has the relocate affected your print quality at all since you are no longer "really" sensing the bed but rather just running a Z endstop? I Really like the relocate that you have done and may do the same to mine. I have had problems with the Z sensor striking tall prints and that would neatly be fixed as you pictured.
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Re: Problems with glass plate on Printrbot Simple Metal

Postby paynterf » 2015-Dec-Thu-09-Dec

blort wrote:Clever!

has the relocate affected your print quality at all since you are no longer "really" sensing the bed but rather just running a Z endstop? I Really like the relocate that you have done and may do the same to mine. I have had problems with the Z sensor striking tall prints and that would neatly be fixed as you pictured.


Can't say for sure, as I just got done with the relocation project, and I've only made a couple of test prints since then. I don't anticipate any problems though, as I now have my glass plate 'dialed in' with my new Harbor Freight dial indicator mounted to the extruder carriage as shown in the attached photos. After shimming appropriately, I have less than 0.1mm variation over the entire print area.

Frank

151217 DialIndicator1.jpg

151217 DialIndicator2.jpg
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Re: Problems with glass plate on Printrbot Simple Metal

Postby paynterf » 2015-Dec-Thu-19-Dec

For anyone who is interested in the ongoing saga of the glass print bed, the whole story (so far) can be found on my blog site at 'Paynters Palace', aka fpaynter.com. See http://fpaynter.com/2015/12/glass-print ... al-part-v/ for the latest post ;-).

Frank
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