Resultaat van een uurtje ontspanning

Er is niets zo ontspannend als het demonteren van oude apparaten (nee, ik hoef niet direct alle zooi te hebben). Een leraar op de HTS zij ons in de eerste les mechanica: "Wilt u weten hoe iets werkt? .... Slopen!". Ziehier de overblijfselen van 4 oude inkjetprinters (waaronder 1 all-in-one). Stappenmotoren, microswitches, encoders, tandwieltjes, schroefjes en veertjes.

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Magnetic ball joints on our printer

We are proud to show some photo's of our working solution for making very simple ball joints for our printer. A few months ago Kees came up with the idea of using magnets to pull ball joints in a ball seat. We have done some dry runs before but did not print because of the lack of an extruder. Because of us both being busy with our work we did not make as fast progress as we would have liked.

The big plus about this joint is the very limited number of parts that are used for this. You need a base (carriage or effector plate) for the seat, a steel ball (ball from a bearing for example),a strong rare earth magnet and a carbon fibre rod.

Furthermore there is no play because of the magnet pulling the ball in the seat, always in the same direction. Another advantage is the big angle that can be reached.

The making:
The rods were made by drilling a hole in the balls (no accuracy needed for this) and gluing 2 balls on the ends of the carbon fibre rod. The important thing is that all the balls on the rods have the have the same center dimension. By making a simple rig for fixing the balls while the glue sets this is relatively easily done.

The effector plate and the carriages that were made for this printer are made with an SLS machine because we did not have a printer ourselves at the time. I'm positive though that this can be made with the normal FDM printing techniques. That's the next goal for us... Making another effector plate and carriages because one printer is not enough for 2 people.

Below some pictures, enjoy!

ball joint with steel ball and magnet

ball joint with steel ball and magnet

It's alive!

This week I've spent my evenings getting the printer to run. The problem is that I want to print above all other stuff that needs to be done before you should be printing. Things like getting the homing to work (no end switches), a heated bed (we don't have a heated bed), leveling the bottom with respect to the x-y movement. The way to quick results is done in buurman-en-buurman style.

Yesterday I tried to use a big round mirror because I though the multiplex base was not level enough. Also with the mirror I could not get the settings right. When moving in the x-y plane the height from the nozzle should stay at the same height. I measured a difference of 3 mm between the middle (0,0) and the end of the working area... Hmmmmmm... I even thought that the mirror was not level. So I went to the hardware store to get some 15x15 cm mirror tiles... They are level. No doubt about that. But the error was still there. (then I double checked the round mirror, and lo and behold. It's as straight as an arrow).

After some measuring and searching I found that the dimensions of the machine that are needed for making the calculations were off. We used a slightly wrong dimension. After updating the firmware a 7 cm movement of the machine was actually 7cm. Further more all was (reasonable) level. Below some visual proof of the result:

Printing an internal spur gear in layers of 0.10 mm

20130526-000108.jpgThe result when I stopped the printer because the rest would take another hour:

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A movie of the printer in progress. The ticking you hear is the filament coil bouncing against a column:

The first filament!

Last thursday I worked with Kees on our 3D printer. It was long overdue because I have been busy working... Until wednesday we had a machine that was moving. We could give some commands, and the machine would move to the designated coordinate.

A few weeks back I had ordered an extruder because making one ourselves would take too long. Thursday we connected it to the electronics and after some modifications in the firmware we could see the extruder nozzle heating up, we could see the temperature, and the stepper motor driving the extruder moved. We only lacked filament.

A friend of Kees had an extruder and 3mm PLA material. So with this we could try to extrude. See below the result... Next week we'll get the steps per mm filament correct and I hope we'll be able to print something then more sophisticated. We're nearly there.

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