Monthly Archives: May 2012

Heated Build Platform Rework

3D Printing on Heated Build Platform

SUMPOD 3D Printer Printing

I’ve been using this heated build platform for a while now and so far been happy with it’s performance. However, for the larger prints and longer print runs, the base of some prints start to warp and become unstuck from the glass on the heated build platform leading to some prints not making it to the end of printing. To keep warping to a minimum, the first layer of the print needs to be stuck down well to the heated build platform. To achieve this, some investigation is needed so that a solution can be considered.

When testing the temperature of the heated build platform I found that when the heating element is powered, the temperature difference went as high as fourteen degrees C on the glass between the thermistor and heating element. I believe this temperature difference, which was happening about every 230 seconds, caused enough contraction and expansion to cause prints to become unstuck from the glass. Clicking and cracking sounds can be heard during printing as the print starts to become unstuck from the heated build platform.

Heated Build Platform Analysis & Rework

Analysis

Armed with a laser guided heat sensor gun, a stop watch and a spread sheet, I set about finding out what was going on. I preheated the glass bed and let it go through the heating cycle a few times before taking the measurements.

I pointed the heat sensor gun at the target and took measurements for the duration of a heating cycle. The targets for this exercise is the glass area above the nichrome wire and the glass area above the thermistor. See the chart below.

3D Printer Heated Build Platform Temperature Graph

3D Printer Heated Build Platform Temperature Graph

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3D Printer Surgery #4 Extruder Upgrade Part 3

3D Printer Extruder loaded with 1.75mm FilamentAirtripper’s Bowden Extruder V3 for 3d printer is now available. Please make the jump for details to:

Airtripper’s Bowden Extruder V3

The new 3D printer 1.75mm filament extruder upgrade is now complete, all the tweaks mentioned in the Extruder Upgrade Part Two are now built in to the unit, plus extra improvements was made to the overall design, including a newly designed idler to accept the cheaper 608 ZZ Skate Bearing to simplify assembly and to keep the overall cost down. All the project files are now on Thingiverse, STL files and the OpenSCAD 3D script file. Check out the rest of this post for bill of materials, printing and assembly tips.

This 3D printer extruder is design to fit the SUMPOD 3D printer without further modification which makes it an ideal upgrade for SUMPOD users. However, due to it’s simple fixing bracket and bowden feed, the extruder can be easily added to the other 3D printer designs.

3D Printer 1.75mm Filament Extruder

3D Printer 1.75mm Filament Extruder

The extruder, because of it’s compact size, is an ideal solution for multi-coloured printing, and also ideal for multi-nozzle 3D printers.

Rubber Pinch Roller
I’ve been testing a rubber pinch roller idler for a while now, and after close inspection of the roller, I can’t see any damage or deformation in the rubber. In my opinion, the rubber pinch roller has performed very well and performed at least as good as a bare ball bearing. However, I’m not going to recommend it for this extruder because I can’t yet provide details that proves it offers better performance than a bare ball bearing idler. For the extra cost to implement it, some proof of superior performance over ball bearing is necessary before recommending it. You will find more details and pictures about the rubber pinch roller in Extruder Upgrade Part 2.

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