Initial Assessment!

I came to this forum because, having built the K8200 and tried my first print, it began well, but then lifted off the bed at the corners.

Sound advice from a number of correspondents saw me cutting a mirror tile to the correct size and clipping it to the bed. This seemed to work initially, but then (probably having set the extruder nozzle too low) the mirror moved, and ruined the print.

My third attempt saw me fixing the mirror to the bed using a spray-mount adhesive (which is supposed to be temporary, but it a swine to remove once it has been heated!). I also followed the tip to use a Pritt stick to help with adhesion. This worked brilliantly, and I managed to print a perfect circuit board cover. The only problem was that the tip worked too well - and I couldn’t get the damned thing off the mirror!

Eventually I carefully levered the miror from the bed (as I didn’t want to apply to much brute force to the bed and mechanism) then finally managed to get the printed cover off the mirror. The result was extremely satisfactory!

So, to those who are experiencing difficulty, I would say the end results are absolutely worth the effort. The critical factor in my case (and, I suspect, many others) is the nozzle to bed distance. I found that a piece of 100gsm paper, folded in half, gave a ‘feeler gauge’ of 0.26mm. Patient readjustment over a considerable period (who the hell designed that adjustment screw on the Z-axis?) eventually gave a consistent gap over the mirror surface. That was when everything worked beautifully.

I also followed the advice to increase the bed temperature to 55 degrees, and paused the job just as it started for a few minutes, to ensure that the mirror had heated up to the full temperature. Very satisfying - sat up til 3am waiting for it to finish!

Overall, I found the kit extremely well organised, and the instructions 99% excellent. There were a few ‘gotchas’ and things that I would do in a different order next time. If I have one suggestion for a major improvement (and huge reduction in build time) it would be the provision of a ready-made wiring loom (or even the components to make your own before installation). I found the need to solder dozens of wires together, shrink-wrap them and then install them very cumbersome. It must surely be possible to supply crimp plugs and individual cables of different sizes for the different current requirements and make a much neater - and more flexible - job.

However, overall, I am delighted with this printer and now need to get stuck into 3D design software so that ! can make something useful!

I’ve glued the mirror on the bed with a glue gun : a few drops on the edges is enough to lock the mirror and are easy to remove if needed.
To adjust the bed you could use springs and only one of the screws : leveling the bed is a lot easier this way.
Pritt works indeed (too) well even with ABS. For PLA hair spray is a very clean way. It sticks well and the resulting surface is perfectly flat and smooth.