Aerogel Insulation for 3D Printers

A heated bed is nearly essential for printing with ABS. Without it, it is difficult to keep parts from warping as the plastic cools. However, heating up a large print bed is difficult and time consuming. It is true that the printer easily heats the hot end to 200C or higher and the bed’s temperature is only half of that. However, the hot end is a small insulated spot and the bed is a large flat surface. It takes a lot of power and time to heat the bed up and keep the temperature stable.

We’ve used cork and even Reflectix with pretty good results. However, [Bill Gertz] wasn’t getting the performance he wanted from conventional material, so he got a piece of aerogel and used it as insulation. Aerogel material is a gel where a gas replaces the liquid part of the gel. Due to the Knudsen effect, the insulating properties of an aerogel may be greater than the gas it contains.

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Heating Up a Printrbot’s Bed

A heated bed for the Printrbot 3D printer

Heated beds for 3D printers help reduce the amount of curling and warping of parts. The warping happens when the part cools and contracts. The heated bed keeps the part warm for the entire print and reduces the warping.

As an upgrade to her Printrbot, [Erin] added a heated bed. The first plan was to DIY one using Nichrome wire, but heated beds are available at low cost. They’re basically just a PCB with a long trace that acts as a resistor. She added a thermistor to monitor temperature and allow for accurate control.

The Printrbot heated bed worked, but didn’t heat up quite quick enough. [Erin] was quick to scratch off the solder mask and solder new leads onto the board. This converted the board into two parallel resistors, halving the resistance and doubling the power.

This version heated up very quickly, but didn’t have a steady heat. The simple control that was being used was insufficient, and a PID controller was needed. This type of control loop helps deal with problems such as oscillations.

The Printrbot’s firmware is based on Marlin, which has PID support disabled by default. After rebuilding the code and flashing, the PID gains could be adjusted using g-codes. With the values tuned, [Erin]’s printer was holding steady heat, and can now print ABS and PLA with minimal warping.