bertho

I just added a heated enclosure for UM1 at : https://www.youmagine.com/designs/bertho-boman--2 Bertho

Thanks Bas, I am interested to read your report. I am monitoring the actual injection force on my UM1 which is very helpful to be able to see any how the system works and how much safety margin there is. Bertho

Hi I am interested too but only for a set of 8 since I have converted to direct drive. Where will they be shipped from? Bertho

The spring removes extruder build tolerances and filament tolerances. It basically provides a constant force on the bearing and the filament against the knurled drive surface. The degree of compression is set by the adjustment nut. It is the same principle as in the upgraded original UM filament drive. Bertho

Thanks Duesentrieb. I do not think it reduces the noise since the steppers and feeders are external and regardless the UM walls act as sound boards. The next installment is the heater assembly & controller. Bertho

I updated the blog with the enclosure top section.

This is better descriptions than I can provide. See: https://www.google.com/search?q=acrylic+solvent+welding&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a&channel=sb That is how aquariums usually are put together. Bertho

I have been working on an enclosure for my Ultimaker and I am happy the way it has turned out so far. It is not suitable for Thingiverse since my Ultimaker is customized and there are several different version of Ultimakers. For construction details and suggestions take a look at: http://vinland.com/blog/ Bertho

Thanks for providing the plugins and the information.

Welcome Bas, The improvements are simple and practical. Good work. It can be simplified a little bit further: Remove the stop for the Bowden so it can be pushed all the way down to the bearing. The Bowden will pull up slightly so there will be clearance when there is force on it. Regardless, it is stainless steel against Teflon so even if it would touch during retraction it is insignificant. See (I tried to insert a picture, clicked on the Image icon and it asked for an URL, no option for a filemanger to select a picture. I copied and pasted a screen capture, which displayed properly, but I got a message saying "format not allowed". What am I missing?) Bertho

It looks good Robert! Alternative to changing software or mirror prints, you can swap the polarity of one of the pairs driving the stepper and it will reverse the direction. Bertho

One source of a clicking belt noise is misaligned pulleys. The belt gradually runs up on the edge of the pulley and then snaps down again. The second one that I have been trying to trace down is a pitch error between the belt and the pulleys. Gradually the belt and pulley gets out of alignment and then it snaps back into the grooves. For example if the belt pitch is 2.5mm and the pulley is 2.5mm. It would happen if the pulley is a little bit too large or too small. Bertho

I am looking for an accurate 3D model of my UM1. I keep upgrading and adding features so having the 3D CAD files would be a big help. I am not referring to laser cut files. Bertho

I have UM1 so I cannot comment on its performance. I did many measurements on the original extruder after my upgrade. See: http://vinland.com/UM_Extruder_Bearing.html http://vinland.com/Extruder_Drive_Force.html Instead of using a platform scale, try using a luggage scale. They work great since they are designed for "pulling". They are very low-cost. I have bought several brands both in China and in the USA and when checking the calibration I have always found them to be accurate. Bertho

Ian, Make sure you have a good hex wrench that does not have worn edges. If you do not have a replacement you can make it like new by carefully, without overheating, grinding off a few mm of the tip and the worn section. Rubber wheels normally have an aluminum center and a grub screw.

calinb lists many good points above. I too like to avoid the heat creeping up the extruder after shut down. To avoid it I slowly feed some extra filament while the head normally cools off. That way cold filament is pushed in so the heat never creeps up and later creates a possible jam at start-up. The actual code is extremely simple: G1 F40 E75 (tweak it to fit your machine) Here is my complete end code: ;End GCode M104 S0 ;extruder heater off M140 S0 ;heated bed heater off (if you have it) G91 ;relative positioning G1 F300 E-5 ;retract the filament a bit G1 Z2.0 F?max_z_speed? ;move straight up G1 X-20.0 Y-20.0 F9000 ;move quickly off the print area G28 X0 Y0 ;home X/Y, so the head is out of the way G1 Z40.0 E5 ;lower the table to leave space for extrusion G1 F40 E75 ;extrude to cool off the head quickly M84 ;steppers off G90 ;absolute positioning

Robert Wrote: The extrusion length will change with the rubber compression since the drive wheel radius will change. I do not know how significant it is and it could be compensated for. Ian wrote : I am thinking for in the direction of rubber from atleast two sides like you said. this way the system grabs the filament in the hand and gently pushes it up.. zero damage to the filament.... better ?? Ian :smile: Gently?? it better grab it really tight :-)

Great info! Thanks! I have ordered the stepper and I also ordered the flexible material. Perfect timing since I need to do some rubber parts. Thanks again, Bertho

How do you plan to latch it? I like symmetrical designs since it keeps the forces symmetrical which helps especially since we are using low-strength materials. Bertho

Interesting subject!! I have been looking at how to further improve the UM1 extruder drive but as usual I am running out of time. I did not realize that UM-2 has changed to direct drive. If I am going to play with this, I might as well go in that direction to be up-to-date. Any suggestions for finding the stepper in the USA and knurled wheel? I am not too enthused with the knurled wheel but it could be a starting point. Bertho

I too slice on a fast computer and print on a dedicated one. I too have multiple versions of G-code from a model so I also really like to have a button that says "Load G-code". Bertho

Success: I tested with an ultrasonic cleaner and laboratory grade Sodium Hydroxide @ 60°C and got a surprise result: http://www.vinland.com/blog/?p=68#more-68 Bertho

With all the questions and problems with temperature control and measurements I got tired of repeating the same comments so I wrote them up as a guide with a little background theory of the measurement principle. See: http://www.vinland.com/blog/ I need to create some mini index or pre-view since all my entries are in on long sequence. I am learning…. Bertho

I finally documented my measurements on my Ultimaker heated bed and hopefully it will help someone creating their own and at least understand it a little better. I have also collected various upgrades that I have made to the UM. See: http://www.vinland.com/blog/ Bertho

I have seen many questions & comments about temperature errors so I very carefully measured the head temperature of my UM using two different K type thermocouples of good quality and two different meters. All readings were taken at the set temperature of 210C with a stable settled down temperature. Both TCs were properly bolted on to the heater aluminum block and wrapped around the block to reduce conduction errors. Meter #1: Fluke 52 TC #1 209.4C TC #2 209.1C Meter #2: Extech 42525 TC #1 210 C TC #2 209 C The Fluke max error @ 210C is +/-0.4C and the TC max error is +/- 1.1C so the measurement accuracy is typically +/-1C. So it appears that I am lucky with my UM and all four measurements are within 1 degree C of the set value. I have no idea how other UM performs since this is a single sample measurement. As I have mentioned before, a properly designed TC measurement setup should be very good. I suspect that many of the reported temperature errors often are measurement errors. It is difficult to accurately measure the temperature since IR is not accurate and temperature probes often do not make proper contact and there is conduction of heat through the measurement leads that will affect the reading. Bertho