Filament Splicer

Project cancelled, click here to read why
The idea for Filament Splicer was born about a month after our Ultimaker 3D Printer was build. As cool as 3D Printing is, printing in one color is boring.

Users of normal, single head FFF/FDM printers are stuck with single color unless they join filament pieces together to produce one multi-colored string. It is not very complicated but process is quite awkward and you will get fed up very quickly.

If you want to have proper, stable filament join you need to have right temperature on the tip of plastic when you connect pieces together. This is hard to achieve when you use some arbitrary heat source. You either underheat or overheat and burn the plastic. Using print head of your printer is best 'ad-hoc' solution but it leaves quite a mess on it, you cannot print when you splice and plastic which is in the head slowly gets burned while you take time to splice your string.

Then, of course there is issue with forming of the joint, carpet knife and fingers where our favorite tools for that job but it took quite a long time to form each joint.

We have had our share of failed prints due to broken joints / stuck filament and finally decided to create a device which will help to splice filament. Initial idea was to create fully automated unit: you place filament ends on copper block, close it, push the button and viola - you have your joint. That was the theory.... In practice this is impossible because PLA and ABS expand during heat-up and contract during cool down, this results in either no joint at all or bubble-filled mess.

Many headache filled days [Even best PLA is really nasty stuff when you breath it in for a while] later we dropped the idea and went for 'open' model with precisely manufactured grooves which help to quickly heat up, connect and form joints.

Thermal insulation was another challenge, we wanted to allow up to 260c temperature but nothing could properly insulate enclosure from hot copper block for prolonged period of time. Ceramic fiber thermal tape can take that heat but one needs a lot of it and then there is itching... Chinese tape is horrible and even best branded, made in USA [ThermoTec] tape is not flawless. We eventually gave up on ceramic fibre and went with PFTA [Teflon] plates. Since PFTA can be outright poisonous at high temperatures, we decided to use high quality - made in Europe material - this way we are sure that maximum temperature of 235c is well within safety limit.