I bought and assembled my Smartrap a couple of months ago, and the first couple of weeks were to be honest a bit of a headache. I knew nothing about 3D printers, and spent many hours trying different solutions to different problems.
I print with PLA onto a cold glass bed, use a 0.4mm Alu Hotend, and print at 200 deg.
Design is done in Openscad, Cura to slice.
Printing is done via SD card and the LCD screen.
15mm brim.
Support material is always 'Touching the bed', and I use 'Lines' as it peels straight off leaving minor clean up.
Problems I have had and solved:
Jammed filament.
Z offset.
Auto levelling.
Prints not sticking to bed.
The jammed filament was solved by stripping the new hotend and making sure that the PTFE liner was allowing filament to slide through unhindered. I also replaced it and made sure that it was a good fit between the threaded section and the hotend. Smooth progression of filament and no escape routes for melted filament.
The Z offset was driving me nuts until I started using the LCD screen to print, I went through stacks of test prints and watched the brim being laid. I kept micro adjusting the offset using Motion/Z offset until it was laying a bead, but never scraping the glass. I ended up with 1.7mm.
I also discovered that if that first layer looks 'shredded' then it was the filament feed too slow, so printed a smooth running spool holder to ensure that there was no friction holding it back.
The auto levelling worked but always seemed to be unable to adjust to the front edge of the glass. The glass also rattled on the support bearing. I resolved this by running a strip of blue tape under the glass where the bearing is located. This removed the noise and lifted the bed by enough to get the auto levelling functioning correctly.
I tried all sorts to solve the print sticking issue. I tried:
Nothing - Even the brim wouldn't stick.
Sugar/Water - Limited success, ok on small parts but failed on large ones.
Lemon Juice - Slightly better, but not effective enough.
Hairspray - Not much success at all.
Blue Tape - The prints stuck to the tape, but the tape would lift off the bed.
Pritt Stick (Office Glue Stick) - Eureka. Very quick and easy to use. No waiting for anything to dry before use, simply scribble on the glass with it, and print. It takes a paint scraper and brute force to get the parts off the bed. I then simply scrape the residue off the glass, it comes off as a white powder, scribble again, and print the next part.
Another interesting aspect is the design of the part. By learning what the printer can print, and how it prints, I now design parts so that the printer can produce a good result. This is probably the most difficult part of the process for a newbie who know nothing about Openscad, but I have learnt that some detail is a non-starter depending on where it is on the part, and some can be added as it will be where the printer can handle it. Writing efficient code means that Openscad will render the image much faster, and is always a good indicator of how well it has been designed. I make great use of Modules, Union, and Difference, using nested code to reduce repetitive commands and keeping structure to it all.
I now no longer touch any adjustments on the printer, just switch it on, scribble the glue, select the part and print. I can quite confidently leave the house for hours and leave it running, knowing that disaster will not strike. I have been through 2kg of PLA with no printing problems at all.
Hope this helps anyone else who is pulling their hair out, pics attached to show the quality I can now achieve.
RobG
