Printing Taulman 910 on Prusa PEI sheet  

Printing Taulman 910 on Prusa PEI sheet

Hi,
I have a Prusa MK3 and have been printing PETG successfully for the last six months and the only failures I have had have been finger problems. I have recently purchased Taulman Alloy 910 which is a nylon based filament as I want to be able to print structural parts.
On researching the issues of printing nylon I found that adhesion to the print plate is a major problem especially if trying to print on the smooth PEI sheet.
I seem to have come up with a simple solution which I thought would be worth sharing.
I first tried just cleaning the sheet with isopropyl alcohol and rubbing a solution of PVA glue onto it ( I am using Bondcrete which I believe is just straight PVA glue). I notice that on the web a lot of people advise to lay multiple layers of PVA glue to the sheet. As I am into woodwork I know that the less glue the stronger the joint so I got a water thinned solution of PVA (around 5:1) and poured some onto a paper towel and just gave it one wiping and let it dry.
Test printing Alloy 910 worked on this however the test prints although not releasing during the print came off easily. I noticed that when pulling the part off it was the interface between the PVA glue and the PEI sheet that failed.
Having some experience with difficulty of painting onto smooth surfaces I got some 800 grit wet and dry sandpaper and lightly rubbed the PEI sheet until it had an even matt appearance. I now repeated the process of cleaning the plate with isopropyl alcohol, and giving the sheet one application of diluted PVA as described above and letting it dry.
The test prints now adheared very well and were quite difficult to remove. Upon removal of the part I noticed that the failure of the joint seemed to be between the part and the PVA glue which indicated an excellent adhesion of the glue to the sheet. Unless I print parts with large footprints I find I can print many parts on unused areas of the sheet before cleaning and giving the sheet a repeat application.
The following is some further information on my experience with printing Alloy 910
The product is highly hygroscopic and as the filament role came with a hole in the packing I decided to dry the roll prior to use. I purchased a Sunbeam Food Lab food dryer and placed it in there for 10hrs at 70 deg C. Upon measuring the weight I notice it got lighter by about 3 grams. The most of this was lost after 6 hrs.
I then fitted roll holder into a clear bucket which I had lying around and also put in a dehydrator pack. This pail has a small hole in it to feed out the filament and stands above the printer (see picture).
Research also showed that printing nylon should be done in an enclosure to ensure even cooling to prevent uneven shrinkage of the part so I build a simple wooden enclosure using 3mm MDF sheet and small beads to hold it together all on a 19mm MDF base plate. The front and top were fitted with polycarbonate clear so that I could observe the print. I have also a temperature probe to ensure the enclosure does not overheat as I am mindful of all the electronics in the printer which need to remain within reasonable temparature levels.
I am printing the 910 using a nozzle temparture of 250degC and a bed temparture of 45degC (for first and following layers).
During the print the enclosure temperature was reached between 31 and 34 deg C
The square part pictured was 30 by 30 with 20 mm hole and printed with no supports. Only the very top is a bit ragged. The sides were parallel from top to bottom. It was printed with a 5 mm brim.
The cylinder has a wall thickness of 4mm and started at 28mm diameter at the base and tapered to its final diameter if 27. 8 within 3 mm with the remainder being parallel. It was printed with a 5 mm brim.
Original was scaled to 100.5 % which is still a bit small.
I think the brim only being one layer thick is a bit useless so where I think a brim is required I will add a thicker brim via cad (Slic3r PE does not give the option of increasing brim thickness). I will then cut it off with some scissors .
I printed a test bearing joint for wishbone suspension of an E trike and picture shows it under test. I don't have scales to measure the tension I have put onto it but I suggest close to 200Kgm. The part elongated but did not fail catastrophically. I note that Taulman make a carbon filled filament which has twice the tensile strength.
Hope prospective 910 users will find this usefull.
Hans, Australia