Heat Shielding

Welding over a long period of time generates high amounts of heat (remember steel melts at around 1400 °C).  In an earlier post about manual 3D printing it was mentioned that regular breaks must be taken in the welding process to avoid overheating of the both the welding apparatus and the print product. In order to prevent the plastic 3D printed parts on our machine from melting it was decided to re-manufacture critical components out of aluminium.

A heat shielded box will be used to protect the rest of the machine from the heat of the product and to contain most of the molten metal bits which fly around. The box is made by bending a 2 mm sheet of aluminium, it is then lined with slabs of light weight, heat resistant tiles. These tiles were thoroughly tested beforehand by welding right on top of them with varying power settings of the machine (note: for 3d printing only the lowest setting will be used). At low power settings the tiles could be picked up by hand immediately after welding. Damage occurred only when large pools of molten steel came in direct contact with the tiles when welding at with the highest power setting. To protect the MIG torch from sparks and molten metal a simple shield was fabricated from sheet aluminium, this was attached to the torch clamp.

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Heat resistant tile after testing, it discolours at high heat but is damaged only when in direct contact with molten steel.

– The Metalprinters

Manual 3D printing with a MIG welder

On Tuesday the 7th we went to metaallokaal, a metal workshop, to play around with some MIG welders and to get additional information on the welding process. Jeroen, the owner of metaallokaal, gave us some advice on which settings to use. During the instruction our group had a collective eureka moment when Jeroen demonstrated a “wrong” setting for the MIG welder. The feed rate and the power setting were both too low to weld on to the thick plate.

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Kemppi KempoMat 2500

We’ve been looking at one of the core components of our metal 3D printer, the MIG welding machine. In our case, the welding machine is a Kemppi 2500 MIG welder. Since we want to be able to control power and feed rate, we needed to know if and how we could digitally control the main settings of the welding machine.  As it turns out, the feed rate can easily be digitally controlled, but the power requires a small servo on the current switch, since this would be easier and require less alterations to the existing welding machine. Tomorrow we will not only continue our work on the welding machine, we will also tie the knot on the open-source 3D polymer printer we’ll base our design upon. We will keep you posted!

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