a5:bed-levelling-probe

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a5:bed-levelling-probe [2019/04/03 08:18]
cs2000
a5:bed-levelling-probe [2019/05/12 06:51] (current)
cs2000 [Setup and Testing]
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 </WRAP> </WRAP>
  
-==== IR Probe Bed Surface Compatibility==== 
-For best results, the sensor needs to sense the reflection of the IR beam from the top surface of the bed. There is a potential problem when the sensor is used with a transparent bed material that reflects infrared light weakly and there is a surface below the transparent material that reflects IR much more strongly.  
  
-**Glass (with or without coatings such as hairspray, PVA or Kapton tape):** Works as-is if placed directly on PCB bed heater or other surface that does not reflect strongly. If there is an aluminium heat spreader or bed plate underneath the glassthen either paint the aluminium surface matt black as suggested aboveor put a sheet of matt black paper between the glass and the aluminium. Coatings on the glass such as the Black Diamond coating affect the trigger height slightly so its advised to flip the glass upside down.+=====Initial Considerations===== 
 +From my testing and learning as a complete newbie to this whole automatic bed levelling jibberishthree things have become vitally importantyou need to pay attention to all three for the system to work.
  
-**PEI:** this is highly transparent to IR so will not workPaint the underside matt black before using adhesive sheet to attach it to the bed plateChanges to the surface finish such as scoring from low nozzle affect the trigger height slightly+==== Levelling the X Axis ==== 
 + First, we need be sure that your X axis carriage is actually level. As the A5 uses two steppers and two threaded rods to hold the carriage in place, this can get out of alignment so one side can be higher than than the other. 
 +  - To correct/check this, move the Z axis as high as it will go and use come calipers to measure the distance from the bottom rail to the frame, this should be identical. 
 +  - If the measurements are out, turn the printer off and use your hand to manually move the threaded rod couplers to move one side up or down. It doesn't matter what height they actually are, just make sure they're the same!  
 + 
 +==== Print Surface ==== 
 +More detail on this is below, but the quick detail is the A5's glass bed is NOT suitable for an IR probe on its own. Glass is a poor reflector of IR light and the Black diamond build surface interferes with the reflection pattern. I would HEAVILLY advise you but a good surface such as PrintBite, I have had amazing consistence with this. 
 + 
 +==== Z Axis Friction ==== 
 +Whatever lubricant JGAurora use on the threaded rods lifting the Z axis is utter garbage. After only 3 weeks, the stuff on my rods had turned all sticky meaning the //tiny// movements the printer has to do were not being performed correctly. This manifested itself in what sounded like a grinding noise coming from both of the Z axis steppers. I would recommend checking yours moves freely, and if youre concerned, clean the old stuff off and replace it with something like Machine Oil, or your preferred choice of lubricant. 
 + 
 +The reason for this is if the motors turn enough to say, raise the bed 1mm, but for 50% of the movement, they stall because of the friction, your next probe measurement is going to be way offI had probes that were (apparently) 44mm offset from probe point 1, that's utter madness and was caused by the motors stalling for a portion of their move on every single measurement point. **Lube up your rods people!** 
 + 
 +See the [[:lubrication|printer lubrication page for some recommendations]]. 
 + 
 + 
 +=====IR Probe Bed Surface Compatibility===== 
 +In order for this to work, the sensor needs to "see" the reflection of the IR beam from the top surface of the bed. There is a potential problem when the sensor is used with a transparent bed material that reflects infrared light weakly and there is a surface below the transparent material that reflects IR much more strongly.  
 + 
 +**Glass (with or without coatings such as hairspray, PVA or Kapton tape):** Works as-is if placed directly on PCB bed heater or other surface that does not reflect strongly. Coatings on the glass such as the Black Diamond coating affect the trigger height hugely so its advised to flip the glass upside down, paint it and install a new surface like PrintBite. 
 + 
 +**PEI:** NOT compatible
  
-**BuildTak:** the dark grey variant works well with the sensor. The white variant is untested, but it should work too.+**BuildTak:** The dark grey variant works well with the sensor. The white variant is untested, but it should work too.
  
 **PrintBite:** Early samples were found to be opaque to IR (so these work OK), but more recent samples are transparent to IR. This means that it needs to be painted black on the underside in order to work well with the IR sensor. However, this is not practical if the PrintBite sheet has the adhesive already attached.On the A5, its suggested to follow the advice as per glass. Install/paint the surface between the PrintBite and the glass bed. **PrintBite:** Early samples were found to be opaque to IR (so these work OK), but more recent samples are transparent to IR. This means that it needs to be painted black on the underside in order to work well with the IR sensor. However, this is not practical if the PrintBite sheet has the adhesive already attached.On the A5, its suggested to follow the advice as per glass. Install/paint the surface between the PrintBite and the glass bed.
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 **Anodised aluminium, with or without PEI coating:** suitable if the finish is matt or semi-matt. **Anodised aluminium, with or without PEI coating:** suitable if the finish is matt or semi-matt.
  
-**Bright Aluminium:** not suitable.+**Bright Aluminium:** NOT compatible
  
-**Mirror:** Not suitable.+**Mirror:** NOT compatible
  
 **Other/Not Listed:** You will have to check yourself if your surface is transparent to IR light, an easy way to do this is with a standard TV remote control.Place your hand in front of the remote control to block the infrared signal and verify that the remote control no longer controls the TV. (Don’t wrap your hand over the front of the remote control). If the remote control still works, you may be too near the TV, you may need to back away and try blocking again. In that case, you'll need to repeat step 1 to verify the remote control works at the farther distance when it isn’t blocked. **Other/Not Listed:** You will have to check yourself if your surface is transparent to IR light, an easy way to do this is with a standard TV remote control.Place your hand in front of the remote control to block the infrared signal and verify that the remote control no longer controls the TV. (Don’t wrap your hand over the front of the remote control). If the remote control still works, you may be too near the TV, you may need to back away and try blocking again. In that case, you'll need to repeat step 1 to verify the remote control works at the farther distance when it isn’t blocked.
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-==== How-To Install IR Probe ====+=====How-To Install IR Probe =====
 Steve Wagg has put together an EXCELLENT [[https://www.thingiverse.com/thing:2750505|guide on performing this mod on thingiverse]]. Steve has a modified version of the community firmware that is ready to go, configured for use with the IR sensor plugged into the **Z-min socket**. Steve Wagg has put together an EXCELLENT [[https://www.thingiverse.com/thing:2750505|guide on performing this mod on thingiverse]]. Steve has a modified version of the community firmware that is ready to go, configured for use with the IR sensor plugged into the **Z-min socket**.
  
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-==== Full Firmware & Hardware Modification Guide ====+=====Full Firmware & Hardware Modification Guide =====
  
-=== What to Buy? ===+=====What to Buy? =====
 Infrared sensor - [[https://miscsolutions.wordpress.com/mini-height-sensor-board/|IR Sensor Link]] Infrared sensor - [[https://miscsolutions.wordpress.com/mini-height-sensor-board/|IR Sensor Link]]
  
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 Or, you'll need you own wire and either DuPont connectors or a 3pin JST Plug and tools to wire this up. Or, you'll need you own wire and either DuPont connectors or a 3pin JST Plug and tools to wire this up.
-=== Firmware Edits ===+ 
 +=====Firmware Edits =====
 Since this is what frightens most people, lets start here.\\ Since this is what frightens most people, lets start here.\\
   * Grab a fresh copy of Marlin 1.1.8c from Sams repository http://sampin.ch/A5-firmware\\   * Grab a fresh copy of Marlin 1.1.8c from Sams repository http://sampin.ch/A5-firmware\\
-  * At the time of writing, you want the file "JG A5 Custom Main Marlin 1.1.8C.zip" 1.1.9 is **NOT** recommended, development hasn't finished on that version yet (14/03/2019)\\+  * At the time of writing, you want the file "JG A5 Custom Main Marlin 1.1.8C.zip". The newer 1.1.9 beta is **NOT** recommended, development hasn't finished on that version yet (14/03/2019)\\
   * Extract the ZIP file and open up the Configuration.h file in Notepad or Arduino IDE 1.8.5 and make the following edits; \\     * Extract the ZIP file and open up the Configuration.h file in Notepad or Arduino IDE 1.8.5 and make the following edits; \\  
  
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 +OPTIONAL - SLOWS DOWN PROBES FOR MORE ACCURACY 
 **Line 717**\\ **Line 717**\\
 Original Original
 <code>#define Z_PROBE_SPEED_SLOW (Z_PROBE_SPEED_FAST / 2)</code> <code>#define Z_PROBE_SPEED_SLOW (Z_PROBE_SPEED_FAST / 2)</code>
 Change To Change To
-<code>#define Z_PROBE_SPEED_SLOW (Z_PROBE_SPEED_FAST / 8)</code>+<code>#define Z_PROBE_SPEED_SLOW (Z_PROBE_SPEED_FAST / 4)</code>
  
  
 +OPTIONAL - SLOWS DOWN PROBES FOR MORE ACCURACY
 **Line 722**\\ **Line 722**\\
 Original Original
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-=== The Glass Bed ===+=====The Glass Bed =====
 The original developer of these mini IR boards has specifically said he designed it to work on glass, which it does but I guess since the original design with ever smaller layer heights on todays 3D printers, the deviation is just unacceptable. Youtuber Thomas Sanladerer ran tests on this sensor and found a deviation of 20 micros, or 0.02mm which is one layer height [[https://youtu.be/il9bNWn66BY?t=286|Link to His Video]] on plain glass, community testing has resulted in WILDLY inaccurate heights, basically, do NOT do this if you plan to use the standard Black Diamond glass as your print surface, it just wont work.  The original developer of these mini IR boards has specifically said he designed it to work on glass, which it does but I guess since the original design with ever smaller layer heights on todays 3D printers, the deviation is just unacceptable. Youtuber Thomas Sanladerer ran tests on this sensor and found a deviation of 20 micros, or 0.02mm which is one layer height [[https://youtu.be/il9bNWn66BY?t=286|Link to His Video]] on plain glass, community testing has resulted in WILDLY inaccurate heights, basically, do NOT do this if you plan to use the standard Black Diamond glass as your print surface, it just wont work. 
  
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-=== Hardware Changes ===+=====Hardware Changes =====
  
   - If you've purchased a pre-made cable, you can skip these steps;   - If you've purchased a pre-made cable, you can skip these steps;
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-=== Setup and Testing ===+=====Setup and Testing =====
 Now the hard parts are done, you need to complete the setup of the IR sensor and do some testing, so lets continue. Now the hard parts are done, you need to complete the setup of the IR sensor and do some testing, so lets continue.
- 
-  - First, we need be sure that your Z axis carriage is actually level. As the A5 uses two steppers and two threaded rods to hold the " carriage in place, this can get out of alignment so one side can be higher than than the other. 
-  - To correct/check this, move the Z axis as high as it will go and use come calipers to measure the distance from the bottom rail to the frame, this should be identical. 
-  - If the measurements are out, turn the printer off and use your hand to manually move the threaded rod couplers to manually move one side up or down. It doesn't matter what height they actually are, just make sure they're the same!  
  
   - Turn on the printer and using the LCD or a GCODE console such as Pronterface, issue a G28 or push the home all axis button on the LCD, otherwise the axis don't respond!\\   - Turn on the printer and using the LCD or a GCODE console such as Pronterface, issue a G28 or push the home all axis button on the LCD, otherwise the axis don't respond!\\
   - Use the LCD in the MOVE menu and Move Z down slowly (0.01mm steps) until the probe triggers. This is when the red LED light comes on.   - Use the LCD in the MOVE menu and Move Z down slowly (0.01mm steps) until the probe triggers. This is when the red LED light comes on.
-  - Take the current Z value on the screen and negate it. (so a value shown of 1.6 becomes -1.6), this is the offset between your print Nozzle and the sensor height. +  - Take the current Z value on the printers LCD screen and negate it. (so a value shown of 1.6 becomes -1.6), this is the offset between your print Nozzle and the sensor height. 
-  - You may find the nozzle wont go low enoughif so, use a GCODE console of some sort (Pronterface) and alter the Z height offset to the value you identified earlierAs default (for safety)the Z offset written in the firmware is mm+    * My Screen showed 1.6mmI perfonally found I needed to add 0.2mm onto thisso my final value became -1.8 
-     * If you want to lower the head by 0.02mm then you would issue the command "M851 Z-1.2" or to raise it by 0.02mm, its "M851 Z-0.8". Yes, INCRESING the number LOWERS the head, backwards to what youd thing logically, but were using a - sign before it, so the logic is correct. Issue a M500 command to saver this value in the EEPROM once you've figured out what it is.\\ +     * If you want to lower the head by 0.02mm then you would issue the command "M851 Z-1.80" or to raise it by 0.02mm, its "M851 Z-1.4". Yes, INCREASING the number LOWERS the head, backwards to what you'd think logically, but were using a - sign before it, so the logic is correct. Issue a M500 command to save this value in the EEPROM once you've figured out what it is. In my case, a value of -1.80 works well.\\ 
-  - Next, do a bed level using the LCD and the print bed levelling knobs so that the bed is as level as you can get it using this method, basically proceed to set the correct 0.2mm layer height as if you don't have an IR sensor.\\  +  - Next, do a bed level using the LCD and the print bed levelling knobs so that the bed is as level as you can get it using this method, basically proceed to set the correct 0.2mm layer height pretending as if you don't have an IR sensor.\\  
      
      
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 G29 is the GCODE to issue a level bed routine. You can run this now I guess to see it working, but in reality, all you need to do is add the following lines AFTER your initial G28 home command in your slicing software. G29 is the GCODE to issue a level bed routine. You can run this now I guess to see it working, but in reality, all you need to do is add the following lines AFTER your initial G28 home command in your slicing software.
  
-**NOTE: make sure you replace the value in the second line with whatever value you identified in step 3 above that gave you an accurate 0.2mm nozzle height. Remember, any G28 Home command after this script will disable UBL again, so avoid placing G28's after this script.**\\+**NOTE: Remember, any G28 Home command after this script will disable UBL again, so avoid placing G28's after this script.**\\
  
-<code>G28 ; Home All Axis +<code>
-M851 Z-1.7 ; Z Offset +
-M500 ; Save to Eeprom+
 G28 ; Home All Axis G28 ; Home All Axis
-G29 Do automated probing of the bed +G29 P1 Mesh Probe Bed 
-M500 ;Save UBL mesh points to EEPROM. +M500 ; Save To EEPROM 
-M420 S1 ; Activate the UBL System</code>+M420 S1 ; Activate Mesh 
 +</code>
  
 And your done! From now on, the printhead will perform an automatic mesh bed level using the IR probe before every single print.  And your done! From now on, the printhead will perform an automatic mesh bed level using the IR probe before every single print. 
  
-In standard probing mode,This adds about 30 seconds to your print time and ensures that crucial first layer goes down perfect every time!+In standard probing mode, This adds about 30 seconds to your print time and ensures that crucial first layer goes down perfect every time!
  
-With my ultra slow mods to get a better probe height, this takes a few minutes per probe cycle. Since we've saved the mesh to the EEPROM, you may wish to do this mesh periodically and just use the below as your start-up commands since we can call the mesh data back from EEPROM.+If you also performed the ultra slow mods to get a better probe height, this takes a few minutes per probe cycle. Since we've saved the mesh to the EEPROM, you may wish to do this mesh periodically and just use the below as your start-up commands since we can call the mesh data back from EEPROM.
  
-<code>G28 ; Home All Axis +<code>
-M851 Z-1.7 ; Z Offset +
-M500 ; Save to Eeprom+
 G28 ; Home All Axis G28 ; Home All Axis
-M420 S1 ; Activate the UBL System from EEPROM saved data</code>+M420 S1 ; Activate Mesh 
 +</code> 
 + 
 +=====Useful Mesh Bed Levelling Commands===== 
 +G29 -  Issue this command to probe the bed and create a mesh using the IR probe\\ 
 +G29 Q - Issue this command to check if mesh bed levelling is enabled\\ 
 +M420 V - Issue this command to view the current mesh data (useful for comparing results)\\ 
 +M500 - Save the current mesh data to EEPROM\\ 
 +M503 - Show the current data in the EEPROM\\ 
 +M420 S1 - Activate the mesh bed levelling data in the print job\\
  
-==== Wiring ====+=====Wiring Photos=====
  
 Hotend Sensor Wiring Hotend Sensor Wiring
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-==== Testing ==== +=====Testing =====
 You can test your ends top function using Pronterface, and entering gcode M119. This will report the status of all the endstops. You can put your finger under the sensor to trigger it, and then run M119 to see if the change in status is reported. You can test your ends top function using Pronterface, and entering gcode M119. This will report the status of all the endstops. You can put your finger under the sensor to trigger it, and then run M119 to see if the change in status is reported.
  
a5/bed-levelling-probe.1554239921.txt.gz · Last modified: 2019/04/03 08:18 by cs2000