Lulzbot Taz 4, 5 or 6 Removable Build Bed Upgrade

by billyd Sep 18, 2015
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Well... almost have everything done and installed. However, I am having an issue with the specified heated bed mat. When hooked up, it pulls a consistent 20A, which blows the RAMBo fuse. If i put a more tolerant 15A fuse in there, I can get the bed to heat for a bit, but it will eventually blow that one as well. Hooking up the multimeter, I can see the 20A being drawn vs the 10A from the stock Lulzbot sheet.

Any ideas? Does yours draw that much current? Bed works fine and heats consistently if I let it draw 20A. I've ordered a replacement Lulzbot heated bed mat and some more Aerogel... but I'd like to know if you've experienced this or if there's any thing to do to fix it?

Well, I went ahead and recompiled the firmware from what I think is the stock source (It's ... impossible to find from Lulzbot it would seem) for the Taz 5. Changing MAX_BED_POWER 135 from the default 206 resolves the issue. I suspect that maybe you had already done this and had forgotten about it? I know you've been playing with your firmware quite a bit, whereas mine has been bone stock up until now.

Can you tell me what firmware you are running right now and/or do you have a link to the source?

Anyway, for anyone else having this issue with the specified silicone pad, changing your value to 135 or less should resolve your issue of blowing fuses. The resistance on my pad when I got it was about 1.2 Ohms, up quite a bit from the ~0.8 of the Lulzbot pad, which accounts for the huge difference in current draw. I'd also be curious to know what your pad resistance is vs mine, at room temp?

Yes your ohms are way too low. That bed is faulty.

Edit nevermind it sounds like you purchased or received the wrong heater.

No, something is wrong with your heater. If you go to the Amazon page here https://www.amazon.com/290x290mm-Silicone-Rubber-Heater-Printer/dp/B00I50G5GU/ref=sr_1_1?ie=UTF8&qid=1488680142&sr=8-1&keywords=290mm+silicone+heater

and read the specs you will see its max current draw is 10 amps. See last line of excerpt below from that page:


This is the ultimate heating element for your 3D printer's bed. This is a premium silicone rubber heater, normally used in industrial environments to heat large tanks of liquid. We had these custom made to be the fastest, most evenly heated elements available. They include a built in 100k thermistor for accurate readings with easy setup. They run off 24v power so no dangerous voltage and they CAN be run directly with some electronics (some electronics may require a relay due to the current draw). We have tested these with a Azteeg X1 and X3 from http://www.panucatt.com as well as the RAMPS 1.4 directly with no problems (YMMV). These heaters are flexible and WILL REQUIRE a flat build surface such as glass to mount to.

290mm x 290mm / 11.75"x11.75"
Durable Silicone Rubber Construction
Extremely Even Distribution of Heat
Industrial Duty Cycles For Long Life
Heats To 120 Degrees C in About ONE Minute (assuming adequate power supply)
Integrated 100k Thermistor For Accurate and Reliable Temperature Readings
Integrated Thermistor Beta Value 3950K
Thermistor Leads Are Insulated and Ready
Draws Up to 10 Amps @ 24v So Make Sure Your Power Supply Can Handle It...a 400W+ or Dedicated 24v Power Supply Is Recommended"

Regarding firmware yes I am using the latest rcbugfix branch of Marlin. It produces fantastic prints but has issues.

If you are comfortable with Arduino make sure the thermistor for the bed heater is set to 1. Also make sure to do the pid optimization.

I found that my enclosure connector for the heat bed connection was faulty. This is a hard to find component, and I ended up just directly wiring the bed and thermistor right to the Rambo with zero connectors. This turned out great because the connectors have significant losses through them and now my bed heats up super fast. But in any case if your bed is functioning properly it should never draw more than 10 amps (if you bought the correct one from Amazon linked above).

Yep, that's exactly what I ordered. It was most definitely not 290mm x 290mm... it was, I believe, 300mm x 300mm. I have contacted them to see about getting a different unit shipped out or something. (From my order link: https://www.amazon.com/gp/product/B00I50G5GU/ref=oh_aui_detailpage_o08_s00?ie=UTF8&psc=1)

I'll look into wiring it directly to the RAMBo... I was wondering how much loss there was between the two. I was half tempted to solder stuff together when I was reassembling but didn't.

Ok. It's not a big deal to peel off the old heater off of the Aerogel, I've done it once myself and was able to reuse the aerogel and put on the new heater.

Nice thing about that silicone adhesive is it is strong enough to keep everything in place, but not so strong that you can't replace the heater if you need to. I replaced mine when I was searching for an issue, which ended up being the enclosure connector.

When you get the new bed, don't cut the wires. Remove the enclosure connector and run both the heater wires and the thermistor wires from the silicone heater direct to the Rambo with no connectors anywhere. This makes for a near zero loss connection and quicker and more stable heating. Then use tie wraps and create necessary strain reliefs to keep the wires from getting tangled or stressing the Rambo board as the Y axis moves.

I tried peeling it off a little and it seemed that the whole top layer of the Aerogel pad came with it. I will peel some more when I get the replacement pad as a backup.

When I wire in to the RAMBo, where do I solder the wires on? I thought the board had connector pins, or does it have solder pads? I'm a little leery of soldering directly on, just because if I want to move/disassemble, it makes it a lot harder... I guess I could just cut the wires if/when that ever becomes an issue and then put some spade connectors on at that point.

Don't use so much adhesive next time and you can remove the pad easier. If you work slowly with a razor you can get it off pretty cleanly. Of course mine was years old and that might have contributed to making it easier to remove. Use a very thin layer of adhesive. The pad will not move.

No just use the connectors on the rambo board. The heater wire connectors just pull out of the Rambo and then just loosen the screw on the connector and pull off the old wire and put the new wire in. Retighten the screw and press the connector back into the board. The thermistor wires use a 2 pin female molex just like the one used near the bed outside the enclosure.

Sounds like a defective heater. Are you using the one from Amazon per the PL?

The lulzbot heater will not work well with this bed system. It's not the right size.

Which Taz do you have?

Wow, looks like we were typing at the same time!

Anyway, to answer your question, I got the one as per the PL. I have the Taz 5.

With regards to the size, the one from the PL is quite a bit too large. There's overhang past the 12"x12" glass and certainly past the aluminum bedding. You can't install the handles without trimming out the silicone pad slightly. I suppose I could have hit a wire, but the thermal camera didn't seem to indicate there were any wires along the edges.

Looking at your pictures, your silicone pad is much smaller than the one I got. The one I received did/does not fit as neatly as the one you have in your pictures. I wonder if they changed up the specs?

Also, I just put my Lulzbot pad over the bed, and even it is slightly too large. It hangs over the sides of the aluminum carriage upgrade as well.

The heater you should have is 290mm square (see the amazon link). It sounds like you purchased or received the wrong heater.

Carbon fiber Y axis replacement tray available from Amazon.com soon. Price is $169.25 shipped. Message me if you are interested to gauge interest on a first production run. See last 6 photos on this thing's page to see the Carbon Fiber Y axis tray and optional 3 point leveling which is superior for leveling the bed. The Carbon fiber tray is extremely light and rigid making adjustment to the bed level easier since the stock Y tray made of aluminum is very flimsy and reacts to adjustments unnecessarily complicating the leveling procedure.

I am working on putting together all the parts for this. I talked to a 3M rep about the 2216 and the primer you mentioned, since it's so hard to acquire and requires HAZMAT certification to ship the primer. He recommended 3M 94 Yellow Tape Primer paired with 3M DP-110 adhesive. Have you tried this combination? I think I'm going to go with this just to see how it works out, unless you've already tried it and found it to be unsuitable. If it doesn't, I'll go with your recommendation, but the 94 Primer and DP-110 are much easier to source and are a lot cheaper.

The links in the parts list should help you locate everything. The primer can be purchased on Ebay in individual bottles (or used to be available there). The 2 part adhesive is on Amazon, along with the dispenser.

I haven't tried the combination you mention. It's important that the bond is strong and can handle 110 C without degrading. You need something fit for glass and ABS plastic and high temperature. There isn't a lot of bearing area between the print and the glass, so the bond has to be really strong or the handles will break off. The combination I recommend when installed per my written instructions is extremely strong and will not break and will last for years. (I still haven't broken a handle off of my glass since I designed this upgrade years ago).

There's no primer to be had on eBay at the moment. The only place I was able to source it from for a reasonable price (not $1000/pint?!?) was Chicago or Dallas @ RS Hughes. Otherwise I had to buy 12 cans of it.

I told the 3M rep what the requirements were and specified the parts would be at 120C for 24+ hours at a time. He said it should stand up to that fine.

I guess we will see! I have 3 sheets of glass (3mm) from Grayglass on the way, so if it fails, I'll just use another sheet with the stuff you mentioned and bite the bullet on the price (Costs $80 for the pint, $20 for shipping and $35 for HAZMAT paperwork, uhg)

Ok too bad about the primer. Yes I know it is tightly controlled stuff I guess I was lucky to get it so cheaply. Unfortunately there is usually a reason when adhesives and primers are commercial grade versus stuff you get at the craft store. They actually work lol. I hope your solution works well. If it does I will edit the PL and change the instructions. Be sure and contact me here with any questions or issues. You are going to love this upgrade.

Btw consider using the 3 point leveling approach I show in the later photographs on this page. It is much better for leveling, since it is true 3 point which is ideal for leveling a plane. The instructions assume the original 4 leg approach but if you look at the photos it is self explanatory. I have also removed my stock Taz Y travel aluminum plate and have replaced it with carbon fiber so it is a rigid plane making leveling even easier.., since the stock Y travel tray flexes during leveling complicating the process a little. Unfortunately the CF tray is quite expensive since the material alone is $100 with shipping. You can source it yourself if you want and use the stock Y tray as a template to drill it, but it's nasty stuff.

I'll let you know how it turns out with regards to the primer and adhesive.

I ordered the tray that was listed in the PL, are you saying there's a different/better tray, or are you talking about the tray the tray on the PL sits on?

If the latter, I would be happy to order one from you or whomever has it available? Is there much involved with swapping it out? I guess I'm not entirely clear on what that upgrade would entail in addition to what's listed here?

No the leveling tray listed in the parts list mounts to the stock Y axis tray. The stock Y axis tray is what I was speaking about. I removed it and replaced it with carbon fiber recently. That is optional. The leveling tray you ordered is required in either case.

I can check and see what it would cost to make one for you. As I said the material alone is $100 delivered. Then it has to be cut to size and drilled. Let me see what I can do.

ps You can try the 3 point leveling with the stock aluminum Y axis tray and see how it goes. (The carbon fiber just provides a rigid plane to level against simplifying the process somewhat). All that changes is you need the trilevelbar print and shorter #6-32 screws (read the first page of this thing near the bottom). You'll also need a 4mm hole through the right side (center) of the stock Y tray. It will all make sense when you put it together.

That would be fantastic if you could do that! I would gladly pay you for your time and effort. Could you incorporate the holes required for the Openbuild Openrails for the Y axes into the plate? That's what's prevented me from doing that conversion, since I don't know how/if I can do the precise hole drilling required.

I ordered some 12mm bars for the X axis, but I'm thinking maybe I should go down the Openrails route for that as well.

I could only offer the stock pattern in the Y axis tray.

It's not magic though, you can source some carbon fiber plate online and drill the pattern yourself if you want to go open rail.

I don't think it's really necessary to do open rail. I have all linear bearings and hardened chrome shafts on my Taz, along with the 12mm upgrade on the xaxis and it is fantastic. I can print very fast, there is no play. And the 12mm xaxis reduces sag to a point where there is no problem printing the entire width of the build plate. Makes leveling easier too because you don't have to compromise with the sag. On the y and z axis with linear bearings and 10mm hardened shafts instead of the stock plastic bushings is all you need for a zero slop printer.

Thank you for the information, I appreciate it! It really helps... my scope creep on the upgrade has gone from the X-Axis only to include the Anti-Wobble Z mod and now the Y axis rods.

If you can supply a drilled plate I can drop in as a replacement, that would be fantastic, as that should true up my printer to the point that any additional gains may not be worth the effort.

Should be in stock at Amazon next week.

I'll get a price for you. Maybe this can be offered as an optional companion upgrade on Amazon with the leveling tray. We'll see.

Comments deleted.

Just a quick public note to say thanks for this -- this has been fantastic on my printer. I did have some trouble with my first bed attempt because I put PEI on it and didn't get the adhesive completely flat (so the surface wasn't flat, which meant I could never level it anyway) but once I redid the glass and fixed that it's been awesome.

I'm using PrintBite on one of my beds and have been really happy with it. I love how easily I can switch bed types (from PEI to PrintBite to bare glass) with this; very nice. I been telling all my friends =]

Added 3 point leveling feature "trilevelbar-reve.stl and new pictures. Including picture of the carbon fiber Y axis replacement tray prototype for easier leveling (super rigid plane to level against).

Add the 3 point leveling to standard aluminum leveling tray and 2 6-32x3/8" flat head screws. Just drill a centered hole on right side of Y axis tray and use existing spring and 6-32 thumb screw.

Carbon fiber Y axis replacement tray available upon special request private message me here if interested.

Billyd - Any issue with using the stock TAZ 5 heater pad? I have a spare one and would like to use that unless there is a reason that I can't. Getting ready to order all the parts and would like to reuse what I can where it is smart.

The larger pad from Lulzbot will interfere with the plastic handles on each end of the bed. So check to see if it can be trimmed without damaging the pad. It would require removing 4mm from each end at the center (about 4-5" in length), Not sure if this can be done.

Other than that it should work fine. When I first did the design I wanted to use the stock pad but Lulzbot was terrible about keeping them in stock so I went away from them. The aluminum leveling tray is expecting a 290mm square heater pad but a bigger one would just hang over the edges (4mm all around for the lulzbot pad) and a smaller one wouldn't reach the edges. In my experience the glass heats up pretty well even on the perimeter where the pad isn't directly underneath and the plastic sticks fine even out there (somewhat surprisingly). So a size mismatch shouldn't matter much from a practical standpoint. The only possible issue would be the location and size of the bumps under the pad for the thermistor and power cables. There could be an interference with the aluminum leveling tray recess but aluminum is easy to work and a file and or dremel could easily take care of any issue like that.

Thank you for the information. Now I know what problems to look out for. Probably just order the Amazon heater and make it simple on myself.

I think that's a good idea. Removing the stock pad from the adhesive is not much fun either. Unless you had an unused one on hand.

Please see edited comment above.

Is it really necessary to reflash the printer for this? The PID values for the heated bed can be changed in gcode, if I'm not completely confused about what it's talking about, and several on the #reprap irc room that I asked about it indicated that most likely the "bang-bang" approach used by the taz by default would likely work with the new heater without changing anything. Am I missing something? I plan to try it, but I discovered I somehow didn't order the molex connectors so I'm waiting on those to finish my install =]

I've also had some trouble with getting the handles to print well -- the magnet indentations aren't very deep -- and keeping the magnets glued in using the silicon glue. Any reason not to glue those with the epoxy stuff as well?

The best thing to do is follow this guide: http://matterhackers.dozuki.com/Guide/PID+Tuning/6

You can use pronterface to send the m codes you don't need mattercontrol. Follow the steps shown except use M303 E-1 S100 C8 (E-1selects the bed to do the optimization). Be sure to get your bed up to about 90 degrees c before starting the optimization otherwise it might time out on you especially if the stock PIDS are very different from the optimized ones. Copy the PID values the optimization returns and send the values using the M304 command (for the bed) and then save with M500. Then you don't have to reflash. I do like to use Arduino though and store all my new changes in config.h so I have a record of it.

I use supports for the magnet indents on the handle print with the indents facing down when printing. They aren't that deep because the magnets should be flush with the bottom when glued in place and they are only 1/16" deep. If you're having trouble with warping use a heavy brim around the perimeter. It's important the handles come out accurately, especially in height. Ideally you want a paper thickness separation between the magnets in the handles and the aluminum tray, with the bed is in place (and handles glued on). This ensures the glass is in full contact with the heater pad. Unfortunately the stock Taz is a little lacking in accuracy. I have done massive upgrading on my system to get it to print really well. All 3 axes linear bushings and rods have been replaced, the bed of course, the extruder, and I am using 12mm rods on the x-axis to prevent sagging. So if you haven't done those upgrade you might have to experiment with scale and print the handles a few times to get the accurately sized.

The silicone I recommend works really well. I suppose you could use the 2216 epoxy too. The silicone is a little easier but it does take longer to cure. So good point. Make sure you keep the outer faces of the magnets clean of any glue.

If you are still struggling to get a good handle print let me know I can post a gcode file if you give me some specific details like nozzle diameter, extruder type, filament diameter etc. I've also noticed on the z stop extension that you may have to tweak the scale a little in x-y depending on the number of shells you print and the print width you set in the slicer. To get it to fit well on the z stop screw head.

One thing about the silicone is you can reuse the magnets in new bed handles if you damage your bed glass and want to make a new bed. If you use the 2216 epoxy those magnets will not be reusable.

Also, if you decide to use PEI over the glass it's easiest to use the same 3M tape that Lulzbot uses. The silicone glue doesn't stick well to PEI.

I have found a much better source for super flat borosilicate glass. Grayglass.net has 4mm borosilicate glass that is much flatter than the McMaster-Carr stuff. About .001 to .003 surface tolerance, whereas the McMaster-Carr glass is up to .008". Unfortunately you have to order 3 12" squares as a minimum order and it's freight shipping so it's $185 total in the USA for 3 glass beds. That actually is only about $10 more per sheet than McMaster, but you have to buy 3. But this glass is far superior.

The other thing to watch out for if you go with GrayGlass.net is the glass is more flat on one side than the other. So before gluing the handles on you need to place it on the leveling tray, put the nozzle close to the bed, disable the steppers and move the everything in x and y and see if the nozzle stays tight to the surface. If it doesn't flip it over and that will likely be the flatter side.

If any of you decide to go with the 4mm glass let me know and I will post the 4mm bed handles.

I also have a super extended version of the Z stop extension (another 6mm taller) for those of you using the bed system with an E3D v6 extruder. Let me know if you need me to post that file as well.

ps A little more information about what to order from Grayglass.....

Ask for 4mm thick Commercial Borofloat borosilicate glass sheet cut to 12" square. Again you'll have to buy 3 to meet the order minimum from them....

I just called them. They said they do not have 4mm glass... only 3mm and 6mm, but the guy didn't specify any minimum order. I told him to send me 2x of each, as they are only $12 per sheet.

Yes sorry the last time I went to order they no longer carried 4mm glass. But 3mm will work great too and heat up even faster. I forgot to update the comment.

I also found another source but it was awhile ago and their name escapes me at the moment. Their glass was really good too, but required an even bigger minimum order so I didn't bother posting about it.

One thing you want to do before you glue your handles on is to do a temporary level test by laying the glass on the existing bed of your taz and test each face of the glass for flatness (you can lay the glass on the bed caddy-cornered and manually move the nozzle all over the surface and test for peaks and valleys). One side is more flat than the other. So it's important to put the flatter side up obviously, before gluing the handles on. The good side is exceptionally flat, much better than the McMaster-Carr glass.

would the plate on amazon work with a additional PrintInZ build plate ?

So long story short the PrintinZ build plate can be used by adhering it to the glass bed assembled according to the installation instructions of this upgrade. You will need an appropriate adhesive that can handle the materials and the heat.

The nice thing about this design is you can have multiple glass bed surfaces each prepared however you like. Hairspray, PEI, PrintinZ, whatever. They can be swapped out depending on what material you are printing with or for any other factors.

It will work with any printing surface that can either be adhered (or clamped*) to the recommended glass. Or it can act as a standalone bed (replace the glass) if it is 12"x12" (305mm square) by at least 1/8" (3mm) thick, and is both rigid and flat. Remember the plate on Amazon is just one component of this upgrade. See the parts list and upgrade instruction documents in the files section of this upgrade.

*If clamps are used they would probably have to clamp to the aluminum tray, around the 12" square glass surface, since there is only about 7.5mm of overhang around the perimeter. There is about 9mm space between the leveling tray and the Y axis tray when installed, so the bottom portion of any clamp used would have to fit in that space.

Nice work! Functional and beautiful!

Thank you! I really enjoy my Taz printer with this bed. Much less frustrating to use.

I dont understand why people are still having trouble with prints sticking too hard or not sticking. I have a taz 4, and I bought a 1/8" thick 12"x24" sheet of PEI from amazon and some 6" 3m tape, cut the sheet in half and stuck it to the top of bed. I have a e3d v6 nozzle and I use elmers purple glue stick with every filament and my prints stick perfect and pop off the bed with the clam nife that came with it. I use 3 layers of glue stick and heat the bed to recommended temps. Also because it is 1/8" thick PEI it never bubbles or rips. Also I print perfect prints with taulman bridge, alloy 910, tglase, tritan etc. I havnt had to re-level the bed in 4 months. If you are still having trouble shoot me an email at suntornpogasic@gmail I Wish everyone could experience trouble free printing like me, it leaves you much more time to print!

This removable bed system can employ any surface you want over the glass. Just like the stock Taz bed is glass with a PEI layer. This upgrade has several other huge advantages over the stock Taz bed and they are clearly listed on this thing's thinginfo page.

This is FANTASTIC!! I used Lulzbot's general bed concept to fabricate a custom 3D printer, but I was scratching my head on how to do exactly this. EXCELLENT work!

Thanks for the kind words. I have been using this bed setup for about 3 months and it is excellent. Add the enclosure I linked to and you can print with any material.