jhertzberg
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Posts posted by jhertzberg
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That makes sense, but if I understand you correctly this means that the orientation of your driving wheel will change relative to the column of filament as the shaft sweeps. Might this twisting snap or weaken the filament? Will the entire hot end rotate with the angle change, or will the filament twist again between the driving wheels and the melt zone? (Sorry if this sounds negative. I really like the idea, and I may be overthinking it.)
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On 1/27/2018 at 2:27 PM, andywalter said:
Yes indeed, I remember someone doing that! But my extruder mechanism is built on a substantial piece of aluminium plate, it's rather large & heavy as it uses dual geared clamp wheels. Besides, I'm thinking about eliminating the bowden tube using that neat ?ZeroG? idea where the extruder motor(s) are placed in a gimbal at one corner, with splined shaft reaching across top of UMO, and all you have then is a clamp-wheel-gripper thing on rotary mount directly above nozzle shaft. I'm going to have a strong 10mm dia threaded shaft, easily enough to take something added to the top of it. I've been impressed by the ability of Replicator 2G to retract very cleanly, thanks to having extruder wheel mounted immediately above the nozzle, not at far end of elastic rod & tube. So I'm thinking of having 2 step motors counter-rotating (maybe geared down as my present extruder is), in gimbal at one corner, 2 carbon-fibre square tubes reaching across UMO and passing through centres of my 2 grooved aluminium clamp-wheels. These wheels will have 4 small but wide roller bearings in the middle, running on the 4 faces of the tubing. Should be torsionally very stiff indeed.
You would still have the masses of your motors to contend with on just the wrong diagonal moves. With all the stiffness you are building into your XY carriage, perhaps you would be better served by keeping the motors stationary, and for each, running a splined shaft up the side (y axis) and through a bevel gear assembly mounted to the slider block, with a second splined shaft running through the head, to the opposite slider block. The additional weight of the bevel gear assembly is probably more than offset by the lack of moving motors and the simpler head.
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5 hours ago, andywalter said:
5) My bowden tube gets a bit stretched when nozzle is at front-left of UMO, so want the nozzle as far right & back as poss to reduce stretch. Won't put at back as visibility more important, but can put it at the right side. So the Y-axis sliders will go at the left side of the new Carriage.
You could relocate your material feeder to eliminate this issue. I think it was David Braam who at one point suspended the feeder inverted above the center of the machine, using a tripod and rubber bands.
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Mine has always been on a solid table, but in years past, UM has hung running printers from bungee cords at crazy angles for trade shows. If the worry is that your printer might walk off the table, try putting it on a rubber mat or some cork. That will reduce noise transfer too.
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I use a four year old Ultimaker Original, and have made several mods over the years. Quick rundown:
- Heated Bed - OMG, why did I wait so long! Virtually no minuses. Big pluses for bed adhesion and smooooth bottoms.
- Direct drive - It works fine, but I don't know how much improvement in print quality it really gave me. I probably could done as well just slowing my jerk settings. The plus is that I have fewer pulleys to worry about. The minus is that I'm always smacking into the protruding motors when fiddling with the feeder.
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Twister blocks - Do this instead of reptar blocks. They make working on your printhead less of a pain.
- Z endstop adjuster - If you change nozzles regularly, it's a must. It's a lot easier to twist a thumbscrew than to dig out your 3mm driver to fuss with the switch height. I can't find the model of the one I use, but this should do.
- Endcaps - Replace the x/y rod endcaps with some that are adjustable for keeping the rods better in place with little friction.
- Fan cowl - Of course. There are so many. Experiment, or do the excellent dual fan upgrade stickied to the top of the hacks forum.
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Printhead bowden clamp - I got tired of the grip on the bowden getting weak, or little blue rings going missing when I did atomic pulls.
- Sound damping - Even before you install the silentstepsticks (I have an installed set too) use some flexible filament to print a feeder standoff and some printer feet. Stick some adhesive backed padding in the bottom of t feet for even more isolation.
- Various extra bits - Spool spinners, belt tensioners, nozzle holders, etc.
- Heated Bed - OMG, why did I wait so long! Virtually no minuses. Big pluses for bed adhesion and smooooth bottoms.
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Is wall thickness the same as shell thickness?
Yes, is the same as shell thickness. It's called wall thickness in Cura.
How do you adjust Gradual Infill Steps? Is that done through Cura or the firmware?If you are using the new version of Cura, use the advanced settings Gradual Infill Steps and Gradual Infill Step Height along with your setting for Infill Density. You can add these to your UI by clicking the gear icon next to the Infill Category and checking the boxes on the resultant dialog.
With this at your disposal, you can set, for example, Infill Density to 20%, Gradual Infill Steps to 2, and Gradual Infill Step Height to 2mm. The result will be an object filled at 5%, until 4mm before the top of the infill area, whereupon the infill will switch to 10%, then at 2mm before the top of the infill area the infill will switch to 20%.
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Does increasing infill improve print quality?
That depends on the object that you are printing. For print quality, if what you mean by that is the best surface representation of the model, the infill percent only has to be high enough so that all features are supported sufficiently and top layers will close and not sag.
Simple designs that taper slowly to a point don't require infill at all. For most everything else, an infill of 20% is usually ample if you are using the usual number of top layers. With Cura 2.3 and higher, you can even save material by setting infill to 20%, then setting Gradual Infill Steps to a 1 or 2 so that the 20% is phased in from 5% or 10% as the printing approaches your top layers.
Does increasing infill improve print durability (i.e. mechanical part)?Once again, it depends. You have to look at what kind of stresses your part will be subjected to. Is it tension, compression, shearing, or some combination? Greater infill can be useful if it is compression, but increasing your wall thickness is generally more useful otherwise.
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Only to a limited extent, since often the optimal settings for a different brand, or even a different color of the same brand, will vary slightly. Some things are obvious, like color inconsistencies, debris, and pocking, but things like underextrusion may be your printer settings.
If I am not happy with a print the first time I use a new filament, I'll do some debugging. I'll print a small calibration object ~50mm high, and raise the temperature about 5C every 10mm, starting at 10C below the stated temp for the filament. Or, I might slow the printer down to 50% speed, and increase it by 10% every few mm of layer height to see if/when underextrusion begins.
This all assumes that you are inspecting the filament before use. You should check the filament diameter at several spots with digital calipers. A variance much greater than +/- 0.05mm from stated diameter will leave you with overextrusion at the high end and underextrusion at the low end. You should also check that it does not snap too easily when bent. I have received filament that was so brittle that the last quarter of the spool was unusable because the filament continually broke as it went from tightly wound on the spool to straight entering the feeder.
Concerning that benchy, it's pretty good, but without seeing the nozzle while it printed I can't be sure why you got that cluster of blobs right above the slight underextrusion, or the unevenness above the door. You should probably remove any obvious material from the outside of your nozzle, perform an atomic pull to clean the inside of the nozzle, and try it again.
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the answers of a support should be at least qualified, if you are so susceptible to a comment, that only those who do not use the internet could be considered an offense, it is better that you change the name of the forum to "Inconclusive Chat" rather than "Modifications and Hacks"
Look at the flair of the user you dissed. Look at mine. Look at yours. The etiquette of this board is not like 4chan. The standard here is to comment as if you are face to face. Many of us do meet with each other at conferences and maker faires. I'll give you the benefit of the doubt that you would not say "Never made use of Google in your life?" to someone you were talking to for the first time at a conference.
Also, user/ultiarjan 's statement, notwithstanding the existence of combination bearings, is correct. The Ultimaker design uses bushings for XY. Combination bearings instead of bushings would be both overkill and a design problem. Given that the movement rod diameter is 8mm, a bearing outer diameter would be ~15mm, rather than the existing bushing outer diameter of 11mm. This would require a redesign of the slider blocks and more clearance inside the case.
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Never made use of Google in your life?
http://www.euro-bearings.com/lin16.html
https://www.nbcorporation.com/product/lineup/strokebush/sre.html
You are new here. We are a supportive forum. Your informative links are very much appreciated. The insulting tone of your comment, not so much.
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Here how the current plate looks like.
As you can see, there is a single hole that we could use.
Currently, there is nothing using that hole, at least on my model.
I'm not sure that this single hole would suffice to clamp the steel bar really tight, and I agree that it would ease a lot the overall project.
Plus, no original parts would need to be modified!
You also can have access to the rearward holes just forward of the four holes surrounding each of the linear bearings. You would just need to swap in a longer M3 screw.
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The tool changer (my project) is a very well working solution with the extra benefit that it doesn't require any modifications to the standard print head. Single extrusion operation just remains the same. It will be available within this year in some way or other (best case would be a complete upgrade kit).
That's great news! Will you cover all Ultimaker models, including Original?
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The Structur3D folks went the syringe and geared extruder route. They even sell a package with the paste extruder integrated with a UM2+. It should be straightforward to adapt their extruder to your toolhead changer. Unfold ~fab uses compressed air and a moineau pump instead of a geared motor, definitely not something for a home use.
I ran into the same five issues as you when I built a syringe extruder, but since I'm looking to print clay I'm now thinking about skipping the high viscosity issue entirely, and doing some variant of a powder bed type approach.
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Am not Medusa, but here's my guess: I find that some parts like to lift off my heated base plate, typically things like the bottom corner of a box when I've built-up a couple of centimetres of wall height; the top layers contract, levering up the bottom. Using a raft can leave a large mess to be cleaned off large area like the bottom of my box, so instead what I often do is extend the bottom of the box by say 10mm with a thin plate, typically .4mm thick, all the way round to form a flange. Then after I've printed maybe 2mm of the box, and well before any lifting starts, I will put something like a steel ruler on top of the flange while the printing continues, and add some small plastic G-clamps or whatever, so that I really clamp the flange down onto the HBP and there's no way it's going to lift up. These clamps usually stick outside the frame of my printer. Maybe meduza's doing the same?
It's because the cooling fan would hit a side panel that is flush.
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Another option for you now would be to buy a Flex3Drive and then print one of the UM2 replacement heads.
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Since you mention that you print hot, I wonder if you are considering enclosing the print area. If you do so, you may want to consider moving the x/y motors out of the enclosure, using Nick Foley's Motor Corner or one of the remixes from Chopmeister or ataraxis. You should switch to GT2 belts while you are in there.
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I have GT2 Belts, 303 teeth, 606mm long, 6mm wide, closed-loop. Those belts should be fine?
They should be. I assume you are not using belt tensioners.
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@ jhertzberg
I don't quite understand what you said, the length of the belts should be ok, I'm not the first one who tried the ones from robotdigg.com.
Belts are sold in many lengths, and if you bought 302 tooth belts instead of 303 tooth, you would have belts that you could stretch to fit, but would be too tight.
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- The belts are no longer loose, but tight.
How tight? IIRC, there was a video on the old instruction wiki where the user strummed the belts to test the tightness by musical pitch (I think it was an F or F#). If your belts are playing a higher pitch, then they are too tight.
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(I am really sorry I can not understand the meaning of the second question clearly,because my English is not good)Do you mean my last point? What I am saying is that a flexible TPU filament such as NinjaFlex will not neatly feed into the extruder, then from the first hobbed gear to the second one, and then out to the bowden tube, if you do not put a channel or some tubing in to control where it goes.
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I see some problems with this design
- There does not seem to be any tension adjustment or manual filament release.
- The same side of the filament is gripped by both of the hobbed gears. This may unduly bend and deform that side, and prints with heavy retraction may fail.
- There are no filament guides. This design won't work well with flexible filaments.
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- There does not seem to be any tension adjustment or manual filament release.
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Looks awesome becky! Are you worried at all about over heating your steppers at all? Im going to be building an enclosure for my UMO+ here in a couple days and my only concern right now it letting the enclosure get too hot since the bed will be at a constant 100c for hours and I dont want anything to over heat.
With the UMO+, you can flip the X and Y motors to the outside of the case. Search Youmagine for ultimaker motor corner. You won't have to worry about them overheating, and print quality even improves. You can avoid needing new rods if you use bearing adapters.
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did it again, not finding anything. At page 3 I thought you ment
I see now 370mm ?
Yes did it once. maybe im blind but cant see some1 telling custom lenghts for x y 8mm.
I dont wanna buy flexible couplings or shafts when Im not clear about both ends.
Have you read through This thread?
So you didn't read post number 3??
You could also use this https://www.youmagine.com/designs/bearing-adapter-for-direct-drive-um-original adapter from @Dim3nsioneer
I found that if you use Nick Foley's direct drive corner, then you need a slightly shorter adapter, so I modified the @Dim3nsioneer adapter a little bit: https://www.youmagine.com/designs/short-bearing-adapter-for-direct-drive
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gris, I am intrigued by the "wings" on the head. Is that to direct airflow from a crossflow fan?
(I am really sorry I can not understand the meaning of the second question clearly,because my English is not good)
Throw away your short belts - direct drive.
in Third party products & modifications
Posted
I'm glad my musing was helpful.
If you hang your filament spool well above the printer, instead of at the rear, you can reduce some of the strain from the twist.