Prusa Mendel Print Surface - Revision history

Gatohaus: Gatohaus moved page PrusaMendel Print Surface to Prusa Mendel Print Surface: camelecase page name complicates search success

2014-02-16T18:33:59Z

Gatohaus moved page PrusaMendel Print Surface to Prusa Mendel Print Surface: camelecase page name complicates search success

← Older revision	Revision as of 18:33, 16 February 2014
(No difference)

Mirage335: /* Ordinary Glass */

2014-01-06T20:31:14Z

Ordinary Glass

← Older revision		Revision as of 20:31, 6 January 2014
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	Tenleytown Ace Hardware is especially helpful, offering cutting service with the glass.		Tenleytown Ace Hardware is especially helpful, offering cutting service with the glass.

	Unfortunately, ordinary glass does tolerate thermal stress well. Although we are in theory using a PCB heater to evenly warm the bed, in practice the thermal gradient from center to outside edge can be high as 30C. Catastrophic failure becomes likely given mechanical stress, spot ~~heatingcooling~~ from some 3D printed parts, or microfractures on a poorly cut edge. Further, ordinary glass may be less rigid, prone to representing complex warped shapes underneath it.		Unfortunately, ordinary glass does tolerate thermal stress well. Although we are in theory using a PCB heater to evenly warm the bed, in practice the thermal gradient from center to outside edge can be high as 30C. Catastrophic failure becomes likely given mechanical stress, spot heating/cooling from some 3D printed parts, or microfractures on a poorly cut edge. Further, ordinary glass may be less rigid, prone to representing complex warped shapes underneath it.

	Optionally ~~include~~ the thin laser cut red plastic, clear plastic, or silicone sheet between ordinary glass and the PCB heater. This will mitigate rapid or uneven heating.		Ordinary glass surfaces should be double pane and no larger than 8.75" * 8.75" . Optionally add the thin laser cut red plastic, clear plastic, or silicone sheet between ordinary glass and the PCB heater. This will mitigate rapid or uneven heating.

	==Plastics==		==Plastics==

Mirage335: /* Swapping Materials */

2014-01-05T00:59:42Z

Swapping Materials

← Older revision		Revision as of 00:59, 5 January 2014
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	# Laser cut foam mat. Serves as thermal insulator, provides a notch for wiring, and slightly improves flatness.		# Laser cut foam mat. Serves as thermal insulator, provides a notch for wiring, and slightly improves flatness.
	# PCB heater.		# PCB heater.
	# Laser cut red plastic, clear plastic, or silicone. Mostly serves as heat spreader and thermal resistor, ~~important~~ for ordinary glass.		# Optional. Laser cut red plastic, clear plastic, or silicone. Mostly serves as heat spreader and thermal resistor, sometimes necessary for ordinary glass.
	# '''User-selected print surface.''' Glass, plastic, the choices are elaborated in the "Surface Materials" section.		# '''User-selected print surface.''' Glass, plastic, the choices are elaborated in the "Surface Materials" section.
	# Foam washers. These are laser cut from the same material as the foam mat, and should not be reused once crushed. Extras are stored in a glass jar.		# Foam washers. These are laser cut from the same material as the foam mat, and should not be reused once crushed. Extras are stored in a glass jar.

Mirage335: /* Ordinary Glass */

2014-01-05T00:47:23Z

Ordinary Glass

← Older revision		Revision as of 00:47, 5 January 2014
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	Unfortunately, ordinary glass does tolerate thermal stress well. Although we are in theory using a PCB heater to evenly warm the bed, in practice the thermal gradient from center to outside edge can be high as 30C. Catastrophic failure becomes likely given mechanical stress, spot heatingcooling from some 3D printed parts, or microfractures on a poorly cut edge. Further, ordinary glass may be less rigid, prone to representing complex warped shapes underneath it.		Unfortunately, ordinary glass does tolerate thermal stress well. Although we are in theory using a PCB heater to evenly warm the bed, in practice the thermal gradient from center to outside edge can be high as 30C. Catastrophic failure becomes likely given mechanical stress, spot heatingcooling from some 3D printed parts, or microfractures on a poorly cut edge. Further, ordinary glass may be less rigid, prone to representing complex warped shapes underneath it.

	~~'''Please remember to keep~~ the thin laser cut red plastic, clear plastic, or silicone sheet between ordinary glass and the PCB heater.~~'''~~ This will mitigate rapid or uneven heating.		Optionally include the thin laser cut red plastic, clear plastic, or silicone sheet between ordinary glass and the PCB heater. This will mitigate rapid or uneven heating.

	==Plastics==		==Plastics==

Mirage335: /* Swapping Materials */

2014-01-04T20:29:40Z

Swapping Materials

← Older revision		Revision as of 20:29, 4 January 2014
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	# Laser cut foam mat. Serves as thermal insulator, provides a notch for wiring, and slightly improves flatness.		# Laser cut foam mat. Serves as thermal insulator, provides a notch for wiring, and slightly improves flatness.
	# PCB heater.		# PCB heater.
	# Laser cut red plastic. Mostly serves as heat spreader and thermal resistor, important for ordinary glass.		# Laser cut red plastic, clear plastic, or silicone. Mostly serves as heat spreader and thermal resistor, important for ordinary glass.
	# '''User-selected print surface.''' Glass, plastic, the choices are elaborated in the "Surface Materials" section.		# '''User-selected print surface.''' Glass, plastic, the choices are elaborated in the "Surface Materials" section.
	# Foam washers. These are laser cut from the same material as the foam mat, and should not be reused once crushed. Extras are stored in a glass jar.		# Foam washers. These are laser cut from the same material as the foam mat, and should not be reused once crushed. Extras are stored in a glass jar.

Mirage335: /* Ordinary Glass */

2014-01-04T19:19:20Z

Ordinary Glass

← Older revision		Revision as of 19:19, 4 January 2014
Line 38:		Line 38:
	Unfortunately, ordinary glass does tolerate thermal stress well. Although we are in theory using a PCB heater to evenly warm the bed, in practice the thermal gradient from center to outside edge can be high as 30C. Catastrophic failure becomes likely given mechanical stress, spot heatingcooling from some 3D printed parts, or microfractures on a poorly cut edge. Further, ordinary glass may be less rigid, prone to representing complex warped shapes underneath it.		Unfortunately, ordinary glass does tolerate thermal stress well. Although we are in theory using a PCB heater to evenly warm the bed, in practice the thermal gradient from center to outside edge can be high as 30C. Catastrophic failure becomes likely given mechanical stress, spot heatingcooling from some 3D printed parts, or microfractures on a poorly cut edge. Further, ordinary glass may be less rigid, prone to representing complex warped shapes underneath it.

	'''Please remember to keep the laser cut red plastic between ordinary glass and the PCB heater.''' This will mitigate rapid or uneven heating.		'''Please remember to keep the thin laser cut red plastic, clear plastic, or silicone sheet between ordinary glass and the PCB heater.''' This will mitigate rapid or uneven heating.

	==Plastics==		==Plastics==

Mirage335 at 19:14, 3 January 2014

2014-01-03T19:14:29Z

← Older revision		Revision as of 19:14, 3 January 2014
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	[[Category:PrusaMendel]]		[[Category:PrusaMendel]]
			=Swapping Materials=
			Changing from glass to acrylic or polycarbonate beds is '''easy'''. '''Just remember the following:'''
			# For glass, use the laser cut foam washers, and don't over tighten.
			# Ordinary glass needs the laser cut plastic as heat spreader and thermal resistor. Not recommended for other materials.
			# For plastic (acrylic/polycarbonate), don't set the bed too warm, or the printed part will be non-removable.

			The full print bed stackup is:
			# Bottom. MDF backing attached to LM8UU bearings and timing belt.
			# Printed, plastic, leveling mat. See "Leveling" section below for details.
			# Laser cut foam mat. Serves as thermal insulator, provides a notch for wiring, and slightly improves flatness.
			# PCB heater.
			# Laser cut red plastic. Mostly serves as heat spreader and thermal resistor, important for ordinary glass.
			# '''User-selected print surface.''' Glass, plastic, the choices are elaborated in the "Surface Materials" section.
			# Foam washers. These are laser cut from the same material as the foam mat, and should not be reused once crushed. Extras are stored in a glass jar.
			# M3 screws and washers. These are bolted directly through mounting holes in all other layers, including glass.

	=Surface Materials=		=Surface Materials=
	By default, we are using an ordinary glass print surface, which has been cut, drilled, and bolted onto the printer. Other surfaces are available, and we plan to upgrade to pyroceramic glass as the default print surface.		By default, we are using an ordinary glass print surface, which has been cut, drilled, and bolted onto the printer. Other surfaces are available, and we plan to upgrade to pyroceramic glass as the default print surface.
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	=Leveling=		=Leveling=
	'''Suggest others do not attempt this without prior experience.''' Anyone contemplating this exercise in frustration needs a lot of patience and a fire extinguisher. Additionally, the end result is difficult to undo if incorrect.		'''Suggest others do not attempt this without prior experience.''' Anyone contemplating this '''exercise in frustration''' needs a ''lot of patience and a fire extinguisher''. Additionally, the end result is difficult to undo if incorrect.

	Built-in alignment between extruder positioning system and print surface is badly warped on our aging Prusa Mendel, taking as many as six polynomial orders to accurately characterize. Consequently, the only reliable process for realigning this complex system is rather complicated, involving a 3D printed and heat-polished leveling mat. It is roughly equivalent to using a CNC mill to finish off its own table.		Built-in alignment between extruder positioning system and print surface is badly warped on our aging Prusa Mendel, taking as many as six polynomial orders to accurately characterize. Consequently, the only reliable process for realigning this complex system is rather complicated, involving a 3D printed and heat-polished leveling mat. It is roughly equivalent to using a CNC mill to finish off its own table.
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	'''Abort'''! If you have started printing the leveling mat, you probably didn't set the Z-axis endstop position well enough. When this happens, do not wait for the printer to put down more than one layer of the leveling mat - it may become infeasible to remove.		'''Abort'''! If you have started printing the leveling mat, you probably didn't set the Z-axis endstop position well enough. When this happens, do not wait for the printer to put down more than one layer of the leveling mat - it may become infeasible to remove.

	Use PLA material, and '''retry printing''' the leveling mat until the first layer is clearly adhered to the intermediate surface.		Use '''PLA material''', and '''retry printing''' the leveling mat until the first layer is clearly adhered to the intermediate surface.

	==Step 5==		==Step 5==

Mirage335 at 19:02, 3 January 2014

2014-01-03T19:02:02Z

← Older revision		Revision as of 19:02, 3 January 2014
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	Obviously, is all good for first layer alignment, warp prevention, and easy part removal at the end of a job.		Obviously, is all good for first layer alignment, warp prevention, and easy part removal at the end of a job.

			'''Please be careful to use the laser cut foam washers for installing glass, and apply as little pressure as possible.''' Tighten all the screws a quarter rotation at a time, just until the glass stops moving downward.

	===Ideal Glass Surface===		===Ideal Glass Surface===
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	Unfortunately, ordinary glass does tolerate thermal stress well. Although we are in theory using a PCB heater to evenly warm the bed, in practice the thermal gradient from center to outside edge can be high as 30C. Catastrophic failure becomes likely given mechanical stress, spot heatingcooling from some 3D printed parts, or microfractures on a poorly cut edge. Further, ordinary glass may be less rigid, prone to representing complex warped shapes underneath it.		Unfortunately, ordinary glass does tolerate thermal stress well. Although we are in theory using a PCB heater to evenly warm the bed, in practice the thermal gradient from center to outside edge can be high as 30C. Catastrophic failure becomes likely given mechanical stress, spot heatingcooling from some 3D printed parts, or microfractures on a poorly cut edge. Further, ordinary glass may be less rigid, prone to representing complex warped shapes underneath it.

			'''Please remember to keep the laser cut red plastic between ordinary glass and the PCB heater.''' This will mitigate rapid or uneven heating.

	==Plastics==		==Plastics==
	Plastics tend to offer extremely tough adhesion, without the quick release behavior offered by glass. While this may be helpful at times, care is needed to prevent parts from permanently binding to the print surface, even if paper or kapton tape layers are used.		Plastics tend to offer extremely tough adhesion, without the quick release behavior offered by glass. While this may be helpful at times, care is needed to prevent parts from permanently binding to the print surface, even if paper or kapton tape layers are used.

	When printing on these surfaces, please set the bed temperature as low as possible. Recommend no more than 45C for PLA.		'''When printing on these surfaces, please set the bed temperature as low as possible. Recommend no more than 45C for PLA.'''

	Additionally, plastic surfaces are inherently less rigid than glass, particularly if thinner than ~5mm.		Additionally, plastic surfaces are inherently less rigid than glass, particularly if thinner than ~5mm.

Mirage335 at 18:57, 3 January 2014

2014-01-03T18:57:46Z

@@ Line 20: / Line 20: @@
 Unfortunately, ordinary glass does tolerate thermal stress well. Although we are in theory using a PCB heater to evenly warm the bed, in practice the thermal gradient from center to outside edge can be high as 30C. Catastrophic failure becomes likely given mechanical stress, spot heatingcooling from some 3D printed parts, or microfractures on a poorly cut edge. Further, ordinary glass may be less rigid, prone to representing complex warped shapes underneath it.
-===Plastics===
+==Plastics==
 Plastics tend to offer extremely tough adhesion, without the quick release behavior offered by glass. While this may be helpful at times, care is needed to prevent parts from permanently binding to the print surface, even if paper or kapton tape layers are used.
@@ Line 27: / Line 27: @@
 Additionally, plastic surfaces are inherently less rigid than glass, particularly if thinner than ~5mm.
-====Heavy Acrylic====
+===Heavy Acrylic===
 An 8.25mm acrylic sheet has been salvaged from a disassembled LCD monitor, and laser cut to fit. At this thickness, rigidity seems to be exceptional. Probably the best choice for laying down a paper tape or kapton printing surface.
-====Polycarbonate====
+===Polycarbonate===
 A 5.75mm polycarbonate sheet has been cut and drilled to fit our printer.

Mirage335: Mirage335 moved page PrusaMendel Glass Bed to PrusaMendel Print Surface

2014-01-03T18:32:41Z

Mirage335 moved page PrusaMendel Glass Bed to PrusaMendel Print Surface

← Older revision	Revision as of 18:32, 3 January 2014
(No difference)