Before the first delivery you see what is still being worked on. In this video we show a few current open issues – and why they arose in the first place. In short: the pellet extruder brings advantages that create work elsewhere.
Why 48 volts rather than only 24
A pellet extruder has a considerably higher throughput and considerably more heating capacity than a filament extruder. That power has to come from the power supplies in the control cabinet.
With a pure 24 volt system you would need very high currents for it – and therefore very large power supplies, or several of them. At 48 volts we manage with less current and can guarantee supply better, particularly for stepper motors and heaters that draw a lot of watts. So we run both voltages: 48 volts alongside the usual 24.
The consequence: more sensors, more wiring
There is considerably more going on at a pellet extruder than at a filament extruder. It is not just one motor and two fans:
- A heating zone with possibly several temperature sensors – we measure not only down in the heater block but also in the feed zone and sometimes in the middle zone. That makes up to three sensors.
- Additional sensors as soon as the pneumatic conveying system is added.
Because our system is scalable, the wiring is a different length depending on the build size. The head hangs at the top, the control cabinet stands below – on a large machine many small cables would have to be routed over a long distance.
The toolhead board: one cable instead of a loom
That is why we are developing our own toolhead boards. The board is mounted directly on the head; every cable runs only the shortest distance to it. The board itself goes out on a four or six pin connector, as you know from manufacturers such as BigTreeTech or LDO.
That one central cable runs into the control cabinet, where an adapter board translates the signal for the Raspberry Pi. Power is supplied centrally at 48 and 24 volts. That removes a considerable tangle of cabling.
What 48 volts brings with it
Most available boards are designed for 24 volts. There are certainly other manufacturers who have developed in this direction – but our system is aimed directly at integrating 48 volts cleanly. Anyone familiar with CE and safety will guess what that means.
Shielded cables are one example. We can no longer simply lay individual cores in the drag chains but need shielding and a very flexible cable that stands up to the drag chain. Otherwise a data cable lying next to a heater cable causes interference and sends false signals.
You notice it: if you want to build at this level – and that is our standard – you take on a number of open issues at the start. We are working through them step by step.
Staying flexible: removable drivers
On most boards the stepper driver is soldered in place. On ours it is removable. So you decide for yourself: 24 or 48 volts at the stepper motor, one heater or two. That covers a broad spectrum.
The boards are not only fitted in our machines. We also want to offer them separately – for any printer intended to run at 48 volts, including self-build or in-house designs. They will then be available individually in our web shop.
In parallel: the control cabinets for the first three machines
In the background the control cabinets for our first three systems are being built. They contain 48 and 24 volt power supplies from Meanwell – state of the art, well known and solid – along with many Siemens components and Finder relays.
The control boards have so far come from BigTreeTech. We want to develop those ourselves in future too, because a lot of functions can be combined in the process. That is one of our larger goals.
Chapters in the video
The video is in German; the chapter titles below link straight to the relevant passage.
- 0:00 · Intro – first delivery and open issues
- 0:16 · The pellet extruder and its advantages
- 0:35 · Why 48 volts rather than only 24
- 1:17 · More sensors, more wiring
- 2:22 · Our own toolhead board: one cable instead of a loom
- 3:02 · Adapter board and central power supply
- 3:42 · CE and EMC: shielded cables in the drag chain
- 4:42 · The board sold separately and removable stepper drivers
- 5:27 · Control cabinet build and components used
- 6:04 · Outlook