Well 4 days solidly working on stuff. My family think I am mad and have not seen me apart from meal times. Still I have made some progress. The picture shows the screwable jewelry box bottom made with ABS. Unfortunately I did not lift the nozzle away at the end hence the blob at the back. Still I am pleased with it.
What have I found out?
1. It takes a lot of force to push the filament through the nozzle and my steppers only just have enough torque to drive ABS through.
2. PLA cannot be driven through my design of extruder as it buckles. There may be more to play with here as I think I may have had the temperature too high causing too much friction in the delivery tube.
3. I cannot get enough torque or friction to drive HDPE through the nozzle.
4. When designing something take time to check it as printing takes a long time and is frustrating when you get it wrong.
5. 3D designing is hard it is better to sketch it out in pencil before starting using a programme.
6. Solidworks is an excellent programme easy to use and the dimensioning facility is really easy to use- I am glad that I can use my school's educational site licence as it is much too expensive to buy.
7.Putting plugs on everything saves hours. I have just discovered railway modelling plugs cheap and easy to use.
8 Thermistors are very delicate and difficult to attach to the nozzle. They work well until you remove a nozzle and then they break easily.
9 Warping is an issue
10 The machine is very reliable, no breakdowns, repeatable movements. The threaded rods and long bolts have now probably in excess of 40 hours run time and no failures
11 Drilling a hole in a threaded rod so that it is concentric is very very difficult.
What am I going to do
1. Go to Wales for 3 days and speak to the family!
2. Try putting a thermistor in a drilled out bolt so that it can be removed/replaced easily without damage. Screw it into place on the brass bar.
3 Buy higher torque stepper motors
4. Modify the pinch wheel extruder block design for the 4th time and get it right this time
5 Blag an old oven to see if extruding at a higher ambient temperature stops warping
6. Use the pinch wheel extruder to try and extrude solder, I can melt it and I can move it through the extruder. Can I combine the two?
7. Do some experiments on how strong the bond is in the first layer and the board/plate that it is made from.
8. Try and increase the speed of the machine above 800 mm/s- M8 rods instead of m6, change the stepper driver settings.;
9. Try and find the optimum settings for starting and stopping.
10. Go back to the original screw drive design and see how well that woprks with stepppers, the new nozzle andPLA/HDPE