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--- a5:bed-levelling-probe [2019/04/01 04:08] – [Full Firmware & Hardware Modification Guide] cs2000
+++ a5:bed-levelling-probe [2019/05/12 06:51] – [Setup and Testing] cs2000
@@ Line 12: / Line 12: @@
 </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 a PCB bed heater or other surface that does not reflect strongly. If there is an aluminium heat spreader or bed plate underneath the glass, then either paint the aluminium surface matt black as suggested above, or 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 jibberish, three things have become vitally important, you need to pay attention to all three for the system to work.
-**PEI:** this is highly transparent to IR so will not work. Paint the underside matt black before using adhesive sheet to attach it to the bed plate. Changes to the surface finish such as scoring from a 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!
-**BuildTak:** the dark grey variant works well with the sensor. The white variant is untested, but it should work too.
+==== 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 off. I 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 a 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.
 **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.
@@ Line 25: / Line 45: @@
 **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.
@@ Line 34: / Line 54: @@
-==== 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**.
@@ Line 40: / Line 60: @@
-==== 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]]
@@ Line 50: / Line 70: @@
 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.\\
   * 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; \\
@@ Line 79: / Line 100: @@
 #define Y_PROBE_OFFSET_FROM_EXTRUDER -30  // Y offset: -front +behind [the nozzle]
 #define Z_PROBE_OFFSET_FROM_EXTRUDER -1.1   // Z offset: -below +above  [the nozzle]</code>
+OPTIONAL - SLOWS DOWN PROBES FOR MORE ACCURACY
+**Line 717**\\
+Original
+<code>#define Z_PROBE_SPEED_SLOW (Z_PROBE_SPEED_FAST / 2)</code>
+Change To
+<code>#define Z_PROBE_SPEED_SLOW (Z_PROBE_SPEED_FAST / 4)</code>
+OPTIONAL - SLOWS DOWN PROBES FOR MORE ACCURACY
+**Line 722**\\
+Original
+<code>//#define MULTIPLE_PROBING 2</code>
+Change To
+<code>#define MULTIPLE_PROBING 3</code>
@@ Line 148: / Line 185: @@
-=== 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. The best way to fix this is to paint the glass to give the IR beam a better material to bounce back from. The exact colour of the paint doesn't really matter, but the even-ness of the coats do. Even a small hair will affect your trigger distances!
+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 best way to fix this is to paint the glass to give the IR beam a better material to bounce back from. The exact colour of the paint doesn't really matter, but the even-ness of the coats do. Even a small hair will affect your trigger distances!
   - Remove the four bed levelling screws and unplug the bed connector
   - Remove the metal clips holding the glass bed to the metal hot plate.
@@ Line 160: / Line 199: @@
   - I then sanded the entire bed with 2000 grit sandpaper to end up with a perfectly smooth matte finish, this step may be unrequired though.
-In my case, I'm also going to be adding a PrintBite build surface rather than use the Black Diamond. I've had really good experience with this over the years, works really well for PLA, ABS, PETG and loads of others. The final sandwich of layers in my case would be;
+As mentioned above, this doesn't really work on the glass bed so I'm also going to be adding a PrintBite build surface rather than use the Black Diamond. I've had really good experience with this over the years, works really well for PLA, ABS, PETG and loads of others. The final sandwich of layers in my case would be;
-Heated Plate > Glass Bed (With Black Diamond coating facing down) > Print Bite build surface.
+Heated Plate > Glass Bed (With Black Diamond coating facing down and painted surface facing up) > Print Bite build surface (stuck to the new painted glass).
-If you're not using a different build surface, just install it back together the same way it came apart. You can now install the bed and heater plate back in its location.
+=====Hardware Changes =====
-=== Hardware Changes ===
   - If you've purchased a pre-made cable, you can skip these steps;
@@ Line 188: / Line 225: @@
-=== 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.
   - 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!\\
-<WRAP center round alert 80%>
-Please Note: If you do a "Home all Axis" from the touchscreen and the nozzle appears to get stuck in mid-air way above your print bed, turn off the printer and manually wind down the two threaded rods on the axis motors by hand using the couplers at the bottom. I don't know why, mine just refused to actually go low enough before I did this. Once the nozzle is just above the print bed, stop manually winding and try a LCD initiated home all axis command again.</WRAP>
   - 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 enough, if so, use a GCODE console of some sort (Pronterface) and alter the Z height offset to the value you identified earlier. As default (for safety), the Z offset written in the firmware is 1 mm.
+    * My Screen showed 1.6mm, I perfonally found I needed to add 0.2mm onto this, so 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.\\
+     * 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 dont 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.\\
 Now that you have an IR probe and a nice level bed, you need to be sure that before every print, you re-level the bed, but this time we can use the new probe to do that!
-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 3d printer 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: 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
+G29 P1 		; Mesh Probe Bed
+M500		; Save To EEPROM
+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.
+In standard probing mode, This adds about 30 seconds to your print time and ensures that crucial first layer goes down perfect every time!
-**NOTE: make sure you replace the value in the first line with whatever value you identified in step 3 above that gave you an accurate 0.2mm nozzle height.**\\
+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
+G28		; Home All Axis
-M500 		; Save to Eeprom
+M420 S1		; Activate Mesh
-G29 P1		; Do automated probing of the bed
+</code>
-G29 S1		; Save UBL mesh points to EEPROM.
-G29 A		; Activate the UBL System</code>
-And your done! From now on, the printhead will perform an automatic mesh bed level using the IR probe before every single print. This adds about 30 seconds to your print time and ensures that crucial first layer goes down perfect every time!
+=====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
@@ Line 230: / Line 281: @@
-==== 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.

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