mastory

I don't think I need another forum. There are already 2 devoted to Ultimaker, A reprap forum, Thingiverse. The experts here are very willing to help out nubes like me. Not to mention the unrelated forums I belong to. I don't think I'll be joining. Thanks anyway. Tough crowd I guess.

I just so happen to have the same problem, and I have a couple ideas. The first of which I have the parts on hand to make the repair if I decide to go forward with it. I went digging in my box of misc plumbing stuff. I found some brass compression fittings that are normally used for connecting a 1/4" water line to a fridge ice maker. There are 3 pcs to the fitting; a nut that goes on the tube prior to connection, then there is a ferule that presses into the tubing, and the threaded piece that he tube is being connected to. My interest right now is the ferule. It has a ID of .135", OD of .165" and is about .66" long with a flute at one end. like this: http://www.alibaba.com/product-gs/448245319/Brass_Tube_Insert_Sleeve_brass_compression.html The filament slides right thru it. I am considering silver soldering the fluted end to the top end of the famous brass tube. The ferules OD should make a very tight press fit into the Bowden tube. The ferule is long enough to pass thru and be clamped by the little white bushing. Since the OD of the bowden tube will be increased with the ferule inside, it should grip much better in the plastic bushing. The silver solder will make a very strong connection and will not melt below 450C. My concerns; What will happen to the bowden tube when the ferrule conducts heat into the first 5/8" of the tubing? I don't yet know if the increased diameter will fit in the white bushing. What material is the bowden tube is made of? What do you guys think? Matt

Good point and thanks. Next I will back off my tensioner to something way less than it is and see what kind of output I get and if the extruder can transmit enough force without stripping the filament. Of course, first I have to fix the hot end of my bowden tube that popped out as a result of the increased filament displacement. I am going to use some of the improvements by others or engineer my own improvement for this. Thinking about the extruder... If an extruder drive could be designed that does not bite into the filament, it could be engineered to slip when overdriving the hot end, but provide a positive feed otherwise. It seems there is a race between delivering enough filament to the hot end and the strength of the bowden tube connection. Am I pushing too hard or is the bowden tube not strong enough? I thought I was just tweaking my machine to have the right amount of feed. So far I have not had melted plastic leak between my bowden and the brass screw. What is prevents this from happening? Is it just not hot enough in that area? Matt

Er.. How so? ddurant, I had not seen the page you are linking until now. It makes sense to me. I need to refer to rerap wiki more often. I was referring to the ultimaker wiki page that covers extruder calibration http://wiki.ultimaker.com/Calibration_and_Print_quality_improvements What does 10,000 units refer to? There is no mention about M92 E14 when running Netfabb. That's a whole other topic, but with the mechanics the same, it is hard to balance that this calibration factor can be so concrete over many machines (with variable feeder tensions and users that seem to make big differences) just by changing software. I really do appreciate the help yourself and the other experienced users offer here. My first comment above may have come across inflammatory. Better words could have been chosen. This learning curve is little frustrating, but I am on the road. As in many things, lesson from failure are most valuable. I think there are a lot more lessons ahead. Thanks.

Well, I can only say from printing for a short time (a few weeks) that in order to get a positive drive without stripping the filament it needs to be tight. At least on my machine. Its not scientific, but on the high side of finger tight. If the math above is definitive, working it backwards from the constant hat is yielding a consistent result (1179), the effective pitch diameter of my drive bolt is 5.59mm. The root diameter of the knurling is about 7mm+/-.25. Its difficult o measure. I don't it is possible for the pitch diameter to be smaller than the root dia. Regardless, now that I have extruder drive that is calibrated, the print is looking really nice including the infill with an adjusted packing density of .95. I will try .90 next and see how that looks. Maybe I can bring the temp down a bit too. That would be great if my bowden tube hadn't just popped out of the hot end. I guess the extra filament displacement and the positive drive worked together and found the weakest point. Matt

A 5% error in the pitch diameter estimate puts it right in the ball park of the 865.888, But that doesn't explain why I have to set at 1179 to get an accurate feed. I was getting prints with the standard setting and obviously better with the 962.5. I think that alot of people haven't calibrated, or maybe compensating some other way like pack density.

The push lock fitting should be quick to attach and detach. The tube may need to be fully seated before you can pull it out. Gently see if the tube is fully bottomed in the fitting. There is a small ring at the tube entrance. To release the tube , you have to push and hold the ring down and the tube should be released. Should pull right out. I used a ratio to find my extruder constant and changed it 1179 and am now within .5mm of 100mm every time I advance 100. It is strange that it is so much greater than the norm. The fill print volume is a a lot higher now, but the layer adhesion seems to be better. I have been running at 220-230C. My gut tells me from watching it I can bring the temp down a bit now. So I was saying the fill looks a bit heavy - its like it gets 'fuzzy' between the rows of threads. to help that I think I will dial down the pack density. Matt

Thanks for your insight MM. The instructions in the wiki are dodgy in my opinion, and don't address the different software options. To be more clear about my measurement, basically I pulled the bowden tube from the fitting at the extruder mechanism so the filament could come right out the top. I unlocked the drive mechanism and pulled the filament thru until I could close it on 'virgin' material. I closed the drive clamp and checked for 'proper' bolt tension. Wrapped a piece of tape around the filament flush with the push lock fitting. Ran the gcode to extrude 100mm. Then measured the displacement of the tape with dial calipers. I will give 1200 a try as the constant. It just seems way out of line from the norm. By the way, I did check that the bolt is clean before testing. Matt

Almost every text string I search returns something like "xxxxx" is too common a search queary to return results. Try searching "calibration" for instance. Working correctly, this would help the users to not make redundant postings. Matt

So I just used Buildmemarlin to install a new copy of marlin. I changed the extruder constant to 865.888 as I have the newer extruder bolt. I made a couple prints (with skeinpypy and pronterface) and thought the threads looked narrow. I decided to check the extruder calibration. with limited code skills, I hacked together the following to extrude 100mm of filament. G21 ;metric values G90 ;absolute positioning G21 G92 X0 Y0 Z0 E0 ;reset software position G21 G92 E0 ;zero the extruded length G21 M1 ;Pause for user input G1 F75 E100 ;extrude 100mm of feed stock M1 ;Clean the nozzle then press YES to continue... G1 F75 E0 ;reverse feed back to zero G92 E0 ;zero the extruded length again G21 M84 There is probably some extra stuff in there, but it did work as I intended - except the resulting feed was only about 71mm. to measure, I took the filament out of the nozzle, pulled the bowden tube and measured the displacement right above the extruder. I built another marlin with 926.5 as the extruder constant and redid the test. This time I extruded only about 79mm of filament. I did find that when I extrude virgin filament, the displacement is slightly longer than when I extrude filament that's already marker by the extruder. Perhaps it feeds 5% more with virgin filament. If I calculate a constant by ratio, I get an extruder constant that would be about 1200 to move 100mm filament. By looking at my print, it shouldn't need a correction equating to 130% of the current setting. Is there something flawed in my understanding of calibrating the extruder? Something wrong with my gcode? Or is Pronterface altering the output? Your thoughts please...

I'm pretty new here and to printing, but I have found 2 thicknesses of copy paper as a feeler gauge between the nozzle and the tape to work pretty well. That's about .008" or .16mm or .2mm Matt

I am thinking of adding some jack screws to the acrylic. By this I mean tapping an array of holes across the bed and installing a plastic set screw in each one. I am thinking maybe 9 holes spaced appropriately. The screws would be mounted from the back side and adjusted to be flush with the build surface. When the tape is applied, the flatness would not be affected. The idea is that when a print is done, just pop off the plate, turn in a set screw or two to release your part. Replace the damaged tape and print on. This would require that the holes are tapped perpendicular to the plate to a high degree of accuracy - best to be done in a milling machine and minimal if any chamfer on the top side. The set screws would also need a suitably qualified surface. A good way to do this might be tap all the holes, install the set screws sightly above the surface, jam nut them, and machine a new finish to the whole thing. Also thinking of drilling and chamfering a small hole right at the 0,0 so a plastic blob can't accumulate there. Maybe changing my start code would also fix this. Matt

Is there a reason to export STL's from cad as Binary or ASCII? Is one better than the other? I have been using binary only because that's the default for my cad program.

I like the reasoning. If an adjustment should be made, the offset can be made in the Gcode right? Is it true with both SF and Netfabb?

Well, I must admit much simpler than what I was thinking.

I am trying to print some round objects that need to be truly round as much as is feasible. I am getting parts that are consistent in diameter in the X and Y directions, but when measured on the diagonal they are somewhat larger. Since I have stock motors, and stock x-y drive system and I am getting consistency in the x and y directions, I am lead to believe the axes are calibrated correctly. This is done in the firmware right?? My prints are coming out slightly over sized, but I think this is due to the outer contour widths. My current concern is shape, not size. My belts are in my judgement snug, but not overly tight. If I tighten them any more, they will wear out prematurely. My 6mm guide shafts are as near to square as I could get them (should have little effect relative to my problem). I don't 'feel' any slop in the drive system. Latest prints sliced with Netfabb and sent with Pronterface. What else if anything should I look into? Matt

So far in just less than 2 weeks of printing, I have only found only generalizations regarding how high the print nozzle should be when the Z axis is zeroed. This hasn't stopped me from making prints, but it has left some doubt as to what is optimal. I have been able to effectively level the bed and make prints with the height approx. .003-.008" (.08-.20mm). I have done this by using copy paper as a feeler gage either single or doubled over and adjusting the leveling screws or the switch to get an even drag resistance. I used my dial calipers to measure the paper. I think real feeler gages are in order. Have them in the garage, but not knowing what might be the ideal setting, it makes little difference. I suppose it makes a difference what your bottom skin settings are, and which slicer is being used. Relative to that, I am asking how you set your nozzle clearance, what distance you set it to, and which slicer you're using. I would hope that a series of rule of thumb standards could be established to take the guesswork out of the process. Matt

My hat is off to you Daid and your projects. I don't presume tell you much if anything. If I am off base, tell me if so. I have a suggestion for a method to fine tune an extruder pitch diameter constant. It depends on your volume algorithms that relate width, speed, thickness, extruder speed. I am suggesting that a gcode is generated to print an array of threads, each a straight line. Each thread would have all variables fixed with the exception being the extruder speed. Each thread would correspond to a certain E92 value. After the print is completed, the threads get measured. Whichever thread is closest to a target width would be selected. Possibly 2 or 3 tests would need to be ran to begin with rather coarse adjustment ranges and finish with a fine tune. Using a method that is directly derived from print results would be better than attempting to calculate/estimate the effective pitch diameter of a knurled diameter pressing with an unknown force against the filament, and an unknown filament durometer. It is given that the extruder head would have to be at a known height from the print bed prior to testing. I am going to start another thread on this. As a beginner at printing, I have had some difficulty related to the nozzle height. Thanks for your dedication to the cause Daid. Matt

I too had leaks using the teflon tape that was suggested in the instructions. I took c ernst's advice and bought some of the high temp sealant he tried. Don't know yet if its going to work or not. In addition to the sealant, I made a fiber washer out of thick paper gasket material from an auto parts store and clamped it between the peek cylinder and the aluminum block. If the sealant doesn't work, I am pretty certain the gasket will work. Also tried a small countersink in the end of the bowdan tube where it seals against the brass tube. I am hoping all these measures will keep me leak free. I will follow up on how it all works out.

This single issue has caused me a lot of trouble. There is no mention of this step on the netfabb set-up page found here: http://wiki.ultimaker.com/NetFabb_Setup_Guide_and_Quick_Introduction Is there a place in Netfabb where I can have this automatically inserted into the Gcode?

My intention is to print the pulley lying flat on the bed. I want to print the hub as a solid, being in the center, with the surrounding pulley face hollow or with 30% infill. The solid area is surrounded by the hollow areas, but in the same layers. The approx dimensions of the hub are 5/8"ID, 1-3/4OD, x 1-3/4Ht, The rim is approx 4-1/2"OD, 4ID and 1-3/4HT. Between the hub and the rim are thin webbing or spokes. I would post a picture but no time cause I have to get to work. First, I will try printing it with everything solid. I am concerned about warping, print time and material usage. Before I do that though, I want to get a handle on Netfabb which I haven't really made a concerted effort at yet. It seems a bit daunting. Thanks for your thoughts

It is disgraceful to buy this knock-off machine. In the spirit of supporting innovation, the original suppliers need to be compensated for their hard work and future research and development. How much much R&D do you think these copy-cats will engage in. They will simply wait for others to do the work and then copy it. I suggest to not offer community support to those who known to own the counterfeit machines. Buy this machine and aid in the demise of innovation.

I just had an idea. Tell me what you think. The pulley is designed as a solid, and it already has spokes as part of the design. The spokes are thin anyway, and the rim can be printed at a lower density. I could overlap multiple solids (each decremented in volume) in the space where I want the solid filling. Maybe the slicer might be fooled into creating 'external' surfaces within the volume of the hub. Does what I am saying make sense? Do any of the slicers work on a model that consists of more than one solid?

Is it possible to print an object that is partially filled solid and the rest at some other fill density say 30%? I need to print a pulley where I want the hub to be solid so I can press in a bushing and the rest with a lower density. I should ask, Is it possible using the tools that I currently have available which include Netfabb and as well as Skeinpypy, Skeinforge, RepG... I suppose it could somehow be modeled that way, but that would not be a very efficient way to use the tools. If so, how? Thanks, Matt

Could be that. I'll try do use the tools while monitoring my system resources. This machine has a: mobile AMD Athlon XP2800+ 960Mb Ram. I don't want you to chase your tail trying to make your stuff work for me on this old hardware. It would be nice if it could work, but not if it requires an inordinate effort. I think I'll install the package on another machine. Save out the Gcode and use the pronter on the old laptop. That way I'll get the advantage of the faster machine, and your presets, but still print in a remote location with the laptop.