Need a solution to keep your bed temperature stable or even want to reach higher temperatures to print ABS? Most 3D printer heated beds waste heat by radiating uselessly through the uninsulated bottom of the bed. This modification uses the new Aerogel Blanket Insulation (from Aerogel Technologies, LLC) to add thermal isolation to the bottom. Instead of wasting the heat by warming the air beneath the bed, the heat now is directed to just the top.
If you are unfamiliar with aerogel (quoting Wikipedia): Aerogel is a synthetic porous ultralight material derived from a gel, in which the liquid component of the gel has been replaced with a gas The result is a solid with extremely low density and low thermal conductivity.
Aerogel Technologies has turned this into a fairly sturdy material that can be used like blanket insulation with a low weight (190 g for our bed) and high thermal resistance (twice that of styrofoam). It seems the stuff is pretty sturdy since the US Postal Service severely crushed our packing box but the material came out unscathed.
If you use the Aerogel Blanket you'll need some additional material to keep the Aerogel dust from shaking out during prints. Dust will cause problems with the prints sticking to the bed.
- Aerogel Blanket or Other Insulation
This guide uses new materials from Aerogel Technologies called SpaceLoft or Cryogel Z Blanket; either can be ordered from BuyAerogel.com in 5 or 10mm thickness. Both are nearly same except that Cryogel Z has a metal film bonded to one side. If you don't want to buy this stuff then you can still improve the thermal isolation by using cardboard or other heat tolerant insulation.
- Heat Tolerant Film (~50° C)
To contain the dust. You'll need a piece large enough to cover the bottom of the blanket. We used Kapton heated bed film, but Kapton isn't required. Not needed if you use Cryogel Z instead of SpaceLoft.
- Heat Tolerant Tape (~120°+ C)
To seal the sides of the blanket. We want to keep the dust from getting on the print bed! This is needed for both materials.
Above and beyond what you would use to disassemble the heated bed, you'll need the following:
- Heavy Duty Scissors
To cut material to shape
- Hobby Knife
To cut holes for bed leveling system and wires
Straight edge to mark material to guide cuts
To mark shape, leveling system and wiring hole cuts (whiteboard marker works the best)
Step 1: Measure Your Current Performance (optional)
We set the bed to an unobtainable temperature and waited for it to stabilize (about 20 to 25 minutes). As you can see from the screenshot the best we could do using the old isolation was about 104 degrees Celsius (° C).
We want to reach at least 110° C to print ABS parts without warpage. Without the enclosure we could only reach about 95° C. No matter we're going to fix that!
Step 2: Measure Clearance and Order Material
Disassemble the bed (for the Felix Printer see the instruction manuals in downloads section) and measure the space available. We ordered the 10mm insulation as a 12" x 12" (30cm x 30cm) square, although larger sizes and thinner sheets are available. As you'll see 10mm was a bit too thick...
Measure clearance with an eye to removing the old bed insulation (should there be any). Aerogel Blanket has an incredibly high insulation value and replacement is better than adding a thinner layer of new. If the insulation is heavily imbedded into the bottom of your bed then measure the remaining clearance. No need to kill your heated bed.
There are two materials from Aerogel Technologies that will work:
This is the plain Aerogel Blanket with a temperature rating up to 200° C. It will need a heat tolerant film on the bottom to contain the dust.
- Cryogel Z
This is the same Aerogel Blanket but with a metal foil bonded to one side. It has the same temperature rating of up to 200° C. If you have no problems with a conductive metal bottom then this may work better. You won't need a bottom film to contain the dust. Don't be fooled by the cryogenic sales pitch.
Take a look at both and select the one that will work best in your situation.
Step 3: Remove Old Isolation (optional)
Now carefully remove the old insulation material. On our Felix 3.1 printer we had created out own using cardboard and steam pipe radiator reflector insulation. Again if the insulation is heavily integrated into the bed just leave it alone.
Step 4: Cut to Size and Apply
Cut the material to size and holes for the leveling system and wiring. You'll want to want to wear gloves as the Aerogel Blanket insulation gives off a nasty highly hydrophilic (drying) dust. The material cuts quite easily with heavy duty scissors or a hobby (X-acto) knife. We don't recommend a utility or box cutter (known in the Netherlands as a Stanley) - it would be like doing surgery with a chainsaw.
Since we ordered SpaceLoft rather than Cryogel Z, we covered the bottom with a used piece of Kapton bed film to contain the dust. If you ordered the Cryogel Z (with the bonded metal film) then you don't have to worry about dust coming out from the bottom, so skip the next paragraph.
If you ordered the SpaceLoft there is a small problem. As the bed moves it will shake dust out. Like all dust this will cause problems with your prints sticking to the bed, so we want to keep it under control. You can probably use any thick plastic (1mm to 2mm thick) that can tolerate temperatures to 50° C. Kapton tape isn't required - we used it since it was going to the trash anyway.
You've probably noticed that we excavated a bit insulation to make room for the bed cantilever on the Felix Printer. The fibrous material cuts extremely easily with a swipe of a sharp X-acto blade. Since this area is tucked behind the cantilever bar, the dust is contained. You should be able to do the same for your areas with tight clearance.
Step 5: Remount the Heated Bed
Nearly there! Now you need to remount the heated bed, ensuring that you're not interfering with the leveling system and not binding the wiring. As you saw in the last step we had a wee bit of a problem with clearance with the cantilever, but it worked out in the end.
Step 6: Seal the Isolation Edges
As pointed out earlier, the dust can be a bit of a problem. We sealed the edges of the blanket with 2.5cm Kapton tape. Just tape from the top of the heated bed to the bonded metal film or whatever you used on the bottom. This tape will need to tolerate the new maximum bed temperature, so double check the temperature rating of the tape before just using anything.
Step 7: Remeasure Your Performance (optional)
We wanted to know how much better the heated bed is performing with the new insulation. We simply set the temperature to our 110° C ABS goal. The printer reached that in 15 minutes, so we set a higher temperature and the temperature kept rising! For our printer, using the 10 mm thick Aerogel Blanket, we stabilized at a maximum temperature just shy of 115° C.
With the new insulation, holding 110° C wan't a problem (see screenshots). We noted that the bed temperature was also much more stable at PLA temperatures and heated a bit quicker.
Step 8: Test by Printing (optional)
Proof is in the printing - we successfully printed ABS after the modification. Now it's time for you to do the same. We suggest that you first try a simple model before you move on to something you truly need. Our favorite has been included here.
That's it and we wish you a successful mod as well.