This is a removable build bed design that you can make as an upgrade for your Taz 4, Taz 5 or Taz 6.
It is comprised of a precision machined, level adjustable, ultra lightweight aluminum tray with magnets and separate square glass bed with ABS handles, also with embedded magnets. The glass bed can be simply pulled off the aluminum tray while still hot, immediately post print. No tools are required for removal or leveling. The bed is held firmly in place by the powerful magnets and friction between the silicone heater pad and the glass. Leveling is achieved via three always easily accessible thumb nuts located underneath the stock Y axis tray. This design has been fully tested for several months by me, and I can happily attest that it works flawlessly.
I use hairspray and an enclosure (See my enclosure design here:http://www.thingiverse.com/thing:746922) , which works perfectly and allows the use of any printing material available provided you have the correct extruder. Some materials may require other surfaces however, and there is no reason why you couldn't cover the glass with PEI, PrintinZ (Or anything else), especially if you prefer not to use an enclosure or hairspray.
This is a huge advantage over stock because you can remove your printouts from the printer while they are still attached to the bed, so you remove them and start printing again quickly. And removing the part (along with the bed), will not throw the printer out of level because you do it away from the machine. Sometimes, on the stock Taz, I had to work so hard to remove a print, the printer would no longer be level ! But with this upgrade, the leveling tray itself never leaves the printer. You can remove the part from the bed in an open and unrestricted area, free to pry (if you're using PEI) as hard as you like without upsetting level. You can also use multiple glass beds and swap them out as you want, dramatically decreasing the time between prints, so you can get more parts out of your printer per day.
The only permanent (this upgrade can easily be undone, but you won't want to) mod to the stock printer is to drill 5/32" (4mm) holes (4x) in the existing aluminum Y travel plate for mounting of the aluminum leveling tray. Leveling is achieved via three knurled thumb nuts at three corners located under the stock Y travel tray. The fourth corner is fixed in height via the printed spacer. The glass is borosilicate and can be 1/8" 3/16" or 1/4" thick. Thicker is sturdier, but takes longer to heat. Beware 1/4" thick takes about 30 minutes to heat up, so I don't recommend it. The 1/8th inch thick glass heats to printing temperature very fast, just a couple minutes or so. 3/16th thick is much stronger, but takes about ~10 minutes to get to 105 C. The Z knob adjustment screw needs to be modded taller since this tray sits slightly higher than stock. But this is achieved with a simple 3D printed part that is pressed onto the existing Z knob.
User installation can be done in less than an hour (assembly of the components will take longer, as the adhesives need to cure overnight). Changes to the heated bed PID values via pronterface is recommended but not required. Otherwise the printer operates as stock.
The entire bed is clear of obstruction so the entire print surface can be used regardless of type of extruder or even a dual extruder. Nothing protrudes above the glass bed surface, anywhere. The stock bed had large protrusions at each corner, which can collide with the print head, especially the dual extruder, if you aren't careful. No more collision worries!
PEI can be omitted (with the use of enclosure) so no more hopelessly stuck parts. Use hairspray for trouble free adhesion.
But any type of surface can easily be added to the glass.
Multiple glass beds (perhaps with different surfaces) can be kept on hand and swapped in seconds. The only adjustment would be the Z knob. Actual level would never change with change of glass bed since the leveling portion never leaves the printer.
The bed is held in place by powerful magnets pulling down creating friction with the silicon heater pad which is in direct contact with the glass. So, the bed won't move unless you want it to, because the friction between the silicone rubber and the glass is very high.
Easy to remove glass beds can be lifted out immediately post print without tools for quick cooling and MUCH easier part removal, all without altering bed level in the printer.
Leveling the bed is much easier than stock as well. It can be done in just a few minutes. The stock version took forever to level and required a hex drive to do it. And access to the screws was sometimes obscured making leveling often an exercise in frustration. But, with this upgrade, no tools are necessary, just adjust the three thumb nuts which are always easy to access, to quickly get your bed system ready to print on.
Update 09-21-2015 Upgrade instructions now available for download!
Update 10-14-2015 Added file Lulzbedspacer.stl.
Update 10-21-2015 Revised Parts list and Instruction manual
Update: 12-8-2015 Aluminum leveling tray component of this upgrade now available message me for details to purchase
Update 04-21-2016 Revised Parts List and Instruction Manual
Update 07-09-2016 Added trilevelbar-reve.stl to provide 3 point leveling feature. This part mounts to the bottom of the aluminum leveling tray with flat head 6-32 x 3/8" long screws (2, replacing existing 6-32x1.25 screws at two corners), with a 6-32 x 1.25" long screw at the center pointing towards the Y axis tray. Apply spring from parts list and 6-32 thumbscrew under stock Y axis tray to create a 3 point leveling system. Coming soon: Carbon fiber Y axis tray replacement for incredible rigidity greatly simplifying leveling and making 3 point leveling even more effective. See new pictures for more details.
Update 12-14-2016 Use with the Taz 6 would require end user to provide mounting for wipe pad. Also if autolevel feature is desired, mounting of conductive pads at corners of bed. The removable bed's mechanical leveling is so simple and stable, the need for auto leveling is questionable at best.
Update 06-28-2017 Carbon fiber Y axis replacement tray available message me for details to purchase.
This is a super light super rigid Y axis tray to replace the flimsy aluminum one on the stock Taz printer. Makes leveling super easy with the removable bed system because adjustments to the springs will not flex the Y axis tray which will make leveling more intuitive. Price is $169.25 shipped in USA. This has the same hole pattern as the stock tray at the bearing connections, but has 3 holes for mounting the removable bed system (with the three point leveling print installed on the leveling tray. Do not use the 4 corner mount method with the CF tray you could damage your printer with too low a z setting in the corner with the standoff as there is no flex in the CF tray. The three point method has springs supporting the entire bed providing the necessary safety cushion in case you set Z too low). See last 6 photos on this page to see carbon fiber tray, 3 point leveling and how it looks mounted.
Update 07-26-2018 Bed Heater not available. Use 300mm square heater (available on Ebay) and trim 5mm off all 4 sides. No problem to do this, will not effect functionality.
Update 09-13-2017 Silicone heater required for this upgrade is now available here: http://www.ebay.com/itm/152256021623 Please note this heater will require 5mm of trimming on the fore and aft edges to fit the handles of the glass. But this is not a problem with this heater. Or you can buy a 290mm square heater direct from China via google search. Sorry the original source of this heater is having problems as a going concern.
See upgrade instructions pdf file for full instructions!
See parts list pdf file for order information for all components.
Update 10/21/2015 Small errors corrected in parts list and instruction manual. Please download again if you downloaded them at a prior date for the most up to date info.
Update 12/9/2015 Parts list updated
Update 1/7/2016 Removed docx files, replaced with pdf files (for instructions and parts list)
Update 3/24/2017 Added file Levelbedtest.stl for help in doing final dialing in of bed level. Print this file after leveling bed as best you can via measurement and then while it is printing adjust three leveling knobs until all lines are about equal thickness.This will get your glass as level as possible given surface tolerances and sag of your printer.