Amound of tolerated flatness of X,Y bed and fan

K8200 3D Printer K8200 - Assembly and user manual
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I’m building the K8200. I’m almost ready. Doing it nice and easy. Very nice quality kit.
Only downside upto now:

  • the fan that has a rotor that drops out spontanious. I have two HP minifans (turbines would be a better name, they ask 720 mA per fan. I think I use them both.
  • one of the aluminum L-pieces had a casting fault and did not fit, but I milled it and now it fits
  • I do not like flatcable. However I give it a try, it is easy to improve if needed.
  • the aluminum of the X/Y carriage is very soft, I think to soft. I allready have some ideas to improve that and flatten the heatplate. But that’s for later.

I allready made some small modifications and before I go on everything must be smooth, flat and without freeplay. (allready spend several hours today on measuring/aligning using several micrometers) I’m doing it at this phase because now it is still easy to change and is a good base for the future and still easy to improve small things.

I’m a bit concerd if I read about all the Z ax problems. I do not understand that. There must be huge forces in play there but if I turn the Z ax with my fingers this goes very smooth and even. I’m I just Lucky or are most user-faults ?? (I read about crude things like drilling the stepper connection. Mine did not fit either but I used a “ruimer” and around 15 minutes to make it a very snug fit (do not know the english word, roamer ? )

I placed the printer on a flat surface, adjusted al 4 (modded) legs until all 4 corners and the Z ax frame are within 0,1 mm alike. After that I removed the hotplate and measures the aluminum plate under it. I mounted a micrometer at the profile that holds the extruder and then moved it over the X and Y axis like when it prints. Modded trhe thumbwheels for more easy use…

I now the question on flatness:.
The lowest bed is within 0.03mm at the four corners. But the top bed that also holds the heather itself is not flat due to the very soft aluminum. Just laying something like a screwdriver on the middle gives a sweep to the micrometer. That is realy bad. But maybe I’m over concerned so how flat is flat ? The Heather will become the next problem. I thinik I make an other more rigid one.

It was out of the box within 0.21 mm between middle and edges.

As stated before, the fan is rather useless. I read a fan is importand so I want to use the 2 “turbines” One on each side and later ad 3D printed nozzles to them. Am I correct it is important the do not cool the extruder and neither the hotplate but only cool down the pla that just left the nozle. (I probably make them adjustable because I’m afraid the blow the stuff I’m printing away)

I probably will make a better powersupply but first I will test this one on my dynamic load.

Fred PA4TIM

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Thanks, I allready ordered one, together with the standalone controller but they are still in backorder. I did not know the mirror could be used together with the heater. I was afraid the FR4 of the Heater and the extra glass would isolate to much heat.

I now measured the final build. I will need something like a mirror because the heatbed deviates plus/minus 0.1 mm. But the 4 corners are equal so the mirror will give no problem.

I tested the Z spindle with a micrometer on radial movement and it looks like it is straight. It runs very smooth. But to be shure I probably mount a metal clamp around the motor.

I drilled holes on the corners of the profiles so the leg are adjustable.
I used epoxy to glue the nuts and a softcopper rivet to the tumbwheels. The heatbed is now very easy and precise to level and if you go to far the tumbwheel is screwed back in a few seconds.
Altered the bolds that operate the microswitches. But I guess everybody does that instead of the rather stupid way the manual tells you. Also mounted the microswithes slightly different and made the lever a bit wider.

Next thing will be a panel with switches for fans, leds, powersupplys etc. After the first test and measurements of the powersupply behaviour I will make a decent power supply with fuses, control lights/switches etc. One for the heat-bed, leds, fans etc. Also a RPM controller for the 3 fans. The one above the controller will be temperature controlled. The two for the extruder will get rpm control (because at full speed they need 1,5A). I have not decisded yet if I will use PWM or an analog lineair control.

I’m complete new in 3D cad design (sketchup) but I like it very much, Two weeks ago I had no clue about 3D printing other then knowing it exists. It is not as hard as I thought it would be (thanks to sketchup) but I think there are a lot of things I have to learn before I get printable designs. My skills are in electronic design/building/measurements, so modding/adding that will be fun.

I bought the printer to make cabinets for electronics projects, knobs for switches and potentiometers, missing parts for restauration of measurement gear, probes etc.

Only thing left to mount is the extruder. Seems there are lots of problems mounting it so I will take my time for that. And then the hardest most boring part, the software/interfacing. (on Linux and/or Windows 8). Setting all parameters, finding out what software etc.

I think I will be ready to test it this week. I will have to make some changes in my lab to install the printer first (it is rather stuffed with lots of measurement gear)

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Update: everything works fine. I did a testprint, a 4x4x1 cm open box with 1 mm thick walls. This is printed without the glass plate.

pa4tim.nl/?p=5020 (here you find some pictures)

The hardest part was getting all the software to coöperate. 123D design works stable on W7, My main PC is an i5 vPro W8 laptop. And there I like to design. 123D works but crashes. I also use other 123D programs to improve the design and that does not even start on W8. So I design in W8. transfer it to W7 to clean up and then transfer it to Ubuntu for printing… the Velleman Repetier software does not work on W7. It gives a graphical preview error and I’m not the only one .with this fault.

But the same version for Linux works very well. Advantage: Slicing takes only half the time it takes on the fast W8 laptop. (repetier works on W8 but I do not want that connected for hours to the printer.

The powersupply seems to work fine. I read about dropping voltage too much so the heatplate warming up takes forever but mine takes only a few minutes and voltage stays correct. So I did not bother to test it on a loadbank. It allready had a ferrite clamp but I added a second just to be sure.

The extruder does not leak a bit so the copper rivets do there job without the need to overstress the nozzle.
The bed seams to be flat enough for such a small print but today the external controller and glassplate arived. I added a spare nut in the frame. I made a small frame for a micrometer clock that I use for aligning the bed.

There is no wobble or strange noises etc from the Zax (nor in any other one) It runs smooth as a baby. So I’m a happy user.