geert_2

The supports have to catch the lowest part of each winding, otherwise that area will print in thin air and fall down like spaghetti. So I think it might be best to have the support run through the center of the windings. As shown in this cut-out. This should print, but the lowest layers of each winding will still be ugly due to the overhang. And then in CAD merge both support and spring, so it is in one piece, otherwise it might not slice correctly. After completion, cutting out the support and sanding will be a pain in the ass, but yeah... Also, make sure you have some soft of baseplate to make it stick to the glass. Otherwise it will come off during printing, roll away, and produce spaghetti. Big overhangs tend to curl up, so the nozzle may bang into them. This requires good bonding to the glass to survive these bangings. These are the two reasons why I would rather try to print it vertically. But I have never printed such a spring, so it is all a bit of educated guessing, and it may take a few tests to get it right.

If your models consists of multiple separate pieces, make sure to align them in your CAD program, so that all bottoms are in the same horizontal plane. Also check if there are no tiny pieces out of view somewhere in the design. If a tiny thing is sitting below the bottom of the other object, then that tiny thing will sit on the glass, and the rest will float. Or in Cura, split the design in separate parts. Any of these should work, I think.

Yes, sometimes designing complex custom supports takes a lot of time. Especially if you need to make special provisions to remove the supports from difficult to access or critical areas. Then you need to design-in all required gaps, connections, openings for inserting pliers and knifes, etc... It may require testing. I consider all this part of the designing process. It is a bit similar to making moulds for casting in traditional arts, like bronze-casting: such moulds also require a huge amount of thinking and trying. I consider arts not only as the creation beautiful things in mind, but also as the *technology to make them a reality*. There is a whole lot of difference between (1) having a beautiful picture in mind; and (2) being able to paint that in oil paints. The painting requires a huge amount of knowledge on perspectives, changes of light with distance, color theory, and mixing pigments and oil bases. It is mastering this knowledge what makes an artist an artist. The same is true for any other art, like music, sculpting, photoshopping, 3D-editing. So I would suggest that you spend the required study- and trial-time to get best results. You won't regret it. Practically, if I had to print such a vase, I would probably add a couple of little plates like this in-between the vertical bars. And then copy and move them around with functions like "pattern" and "revolve" (or whatever their names in your software), and finally merge everything. I would probably do a set at 1/3rd and 2/3rd height. But I would first try the concept on a small test piece, before doing the whole vase. It will probably require a few iterations. Designing this plate only takes a few minutes. And cutting these out will require post-processing and sanding.

Is it the black block? Or is the sound coming from the rubber belt rubbing agains the flanges of the pulley wheels? I had the last problem in the back left corner. But it was very difficult to find the exact location of the sound. While printing a tiny test piece in a corner, try to carefully push the belt sideways. In my case this made a big difference to the sound. Or manually move the head when the printer is switched off, and then gently push the belts and blocks sideways to find the cause. My solution was to carefully lubricate the edge (only the edge, not the flat part or the teeth) of the rubber belt with inert silicone grease. The sort of transparent white grease that is also used on car door rubbers in winter. Do not use petroleum oils and greases on rubber belts: this may damage them. Silicone grease is much more chemically inert.

The lamps should not have that brown spot in the middle of the yellow phosphor. White LEDs are actually blue LED chips, with a layer of phosphor on top of them. This phosphor converts some of the high-energy blue, violet and UV-light into lower energy green, yellow and red light. This is balanced so that we percieve cool white or warm white, depending on the composition. But the high energy of the blue chip may burn into the phosphor and destroy it over time. Just like UV-light typically destroys plastics and paints. This is why some "white" LED lamps turn greenish after some time, since more blue shines through. You see this in LED street lamps and pocket lamps. I am not sure, but maybe this has also happened here? Maybe up to the point where the phosphor has totally degraded into some sort of coal?

The reason why I wrote this is because in one of my UM2 (non-plus) there is a little bit of play when fixing the 4 mounting screws of the feeder. If I push the feeder totally to one direction, and then fix the 4 screws, it is nearly impossible to insert filament afterwards. If I center the feeder or push it to the other side and then fix the screws, inserting filament goes easy. I have to get the right balance. This is only a few tenths of a mm difference, but since PLA is not very compressible, it seems to make a difference. So I could imagine that the opposite might also occur: not enough grip, and slipping? But as said, this is guessing, trying to find a direction...

PLA is totally unsuitable for hot liquids, or for any other hot application. It starts to soften and deform around 50°C (~122°F). It will even deform in a car in mild sunny weather, in spring or autumn. We are not even talking about summer. Each time you go over the softening temperature, of course it may deform further, also depending on the loads applied to it, and on residual internal stresses. For your application you really need a high-temp 3D-printing material, thus one that has a glass transition temperature (=point where it starts softening) of more than 100°C. But I don't have enough experience with high-temp materials to recommend a specific product, so I will leave that answer to others. It will probably go in the direction of PET or polyester-like products: these are still easy to print (contrary to ABS and PC which are more difficult to print).

I have no idea, so I will leave that question to the Ultimaker people and distributors.

If automatic pre- or suffixes would be desirable for some people, maybe a *versatile system based on parameters* might be best? Similar to the one used by IrfanView? But then of course adapted to 3D-printing instead of photos. In IrfanView you use the parameter "$N" as a placeholder for the original filename, and you can add your own text around it as you like. There are other placeholders for file size (in bytes), dimensions (in pixels), zoom factor, exif-data, file-date, Nikon or Canon camera specs, etc... See the screendumps with syntax below. Personally, I would prefer no automatic pre- or suffix at all, since I may add different abbreviations for material (PLA, PET, NGEN,...), for high and low temps, high and low speed, high and low flows, upper part and lower part of a design, model-date, etc... It all depends on the situation. And the filenames have to fit in the 20-characters limitation of my UM2-display. So I can not use a fixed syntax. Most people who could use a fixed syntax, will use a different one. So it has to be versatile. Screendumps of IrfanView text syntax for: on-screen display of filenames, for batch-renaming, HTML-export, etc... (see red box):

I think a defective power supply, or one that is deteriorating, might also cause this? If it would cause a drop in voltage?

If I had to print a spring on my single nozzle UM2, I would probably add a very thin wall between the windings (only one line), and cut that out later, as in the quick demo image below. I would also add a base-plate for bonding to the glass. I think it is best to use concentric infill (or make the shell bigger than the spring wire), instead of using diagonal infill, so that the print lines run along the curve of the spring. This should improve strength. And print slow and warm enough for good layer bonding, but not too hot so it does not sag. It might take some trial and error. Show us the results.

Could a misaligned feeder cause such issues? For example if it is mounted a bit too far to the left or right, so that the clamping of the filament doesn't work well due to misalignment? Or if the knurled wheel is sitting too deep, so it grips the filament only partially (=on the edge of the knurls, or halfway off), and has not enough traction? Just guessing...

Maybe you could modify the bearings, so the spool can't be pulled up? Maybe add some sort of cap or guide to the upper part of the bearings? The older UM2 printers (which I have) are sensitive to underextrusion when stiff filament like PLA is near the end of the spool. The filament acts as a very strong spring that resists unwinding (this is one problem), and the narrow bending radius of the stiff filament causes huge friction in the bowden tube and in the print head and nozzle (this is a second problem). A simple solution that eliminates both problems, is to manually unwind a little bit of filament, then wind it around a skater wheel (7cm diameter) in the opposite direction, so that it is straightened. Then I straighten the next few centimeters. After I have done a few meters in this way, I roll the filament up on the spool again. But now it is sitting very loose, with a bending radius of ca. 30...40cm, instead of 10cm. Thus the bending radius is now about identical as that of the bowden tube. So the resistance to unwinding of the spring is gone, and the friction in the bowden tube and nozzle are very low. This straightening takes only a minute, and can be done while the printer is warming up. It works very well for my models, which only require a few meters of filament, and a few hours to print. For huge models that take a long time, or for overnight printing, this method is less suitable, of course. See the photo. The yellow clamp slides freely around the edge of the spool, and it prevents the filament from falling off sideways, and from getting tangled up. It also prevents the spool from unwinding itself during straightening of the filament. But I don't know if all this is compatible with drying boxes? Or maybe you could develop a derivation of this idea?

A couple of months ago there has been a discussion about how to calculate price, including all details. This was very well written up. But I don't remember the main users. Maybe you can find it via the search function?

In biomedical sciences people often use peristaltic pumps to transport liquids and thin pastes (=with a consistency similar to sirup, honey, yoghurt). For example to inject dead bodies with formol or other preservatives. But this will not work for thick pastes like choco, butter, thick glue, thick silicone. It all depends on the materials you want to extrude, and on the way they are delivered to you. If in bulk or in plastic bags like blood and water in hospitals then it should work. If in standard industrial silicone or glue syringes it will be very difficult. If you are willing to do a bit of development, I think such a peristaltic pump concept might work for 3D-printing too. Connect the feeder motor to the shaft of the peristaltic pump (maybe via a reduction gear for more power), adjust e-steps, and instead of a bowden tube, use a silicone tube with a nozzle. In an UMO or UM2 you might be able to use the build-in provisions for the never unused second feeder and nozzle? At least, if the electronics board can handle a second feeder motor (I don't know which UM-models do have driver chips for a second feeder)? Google "peristaltic pumps" > images. Maybe you could get some inspiration from these areas?

Yes indeed, no Mac version... Wine is good for simple programs like "Notepad", or simple old games consisting of only a few files. But I doubt if you can get a very complicated 3d-editing package running in it, because of the graphics requirements? I know very little about Mac and Linux, apart from a little bit of Knoppix Linux (=live DVD) and hard disk partitioning. It is possible to run DesignSpark Mechanical in a VirtualBox virtual machine, with a Windows 7 client on a Windows 7 host. I got that working as a test. But since VirtualBox has to emulate all hardware, including graphics cards, it runs very slowly. I have no experience with emulators like Parallels on Mac. If you have an older Windows computer with a suitable graphics card (requires OpenGL 2.0, I think?), thus no onboard-graphics, that might be your best bet. I once had it running on an 8 years old machine.

I have no experience with dual-nozzle printers using dedicated support material, so I won't comment on that. But in single-nozzle printers like the UM2 you can design the support as part of the model in your CAD program. Theoretically it doesn't matter if the pieces are connected or not. Both will slice and print. However, if totally unconnected, the support pieces might fall down of course, or they might sag too much. So it is best to design-in tiny connection strands, which you cut off later. Also, tiny gaps between supports and real model will cause occasional hairs and strings, which you also need to post process later. Before doing this on the whole vase, thoroughly try and refine the concept on a simple test piece that doesn't waste too much time and material. It might take a few iterations. Steep overhangs may sag down, or may curl up. For example: if I want to print this table below without supports all the way down to the floor (which would destroy the text), then I need a sort of "hanging supports" for the overhangs. This was just a quick test to try the effect on my printers. The great idea came from user smartavionics, who is developing an automated method for bridges. You might consider a similar concept to stabilise the vertical bars. This is a small model: the walls are 1mm thick, and the table is ca 15mm high. Printed in PLA, 0.1mm layer height, 0.4mm nozzle, probably at 210°C and 50mm/s. The connection strands are 0.5mm wide and 0.2mm high. If I remember all this well... The concept: table with overhangs. The hanging parts with the ribs are the supports. Raw print. In the center piece of the bridge, the supports tend to sag down. At the outward edges, the support tends to curl up. The staircase in the design minimises this effect, compared to a triangular shape, but still. Print after removal of the supports. Text characters are 3.5mm cap height.

Maybe you are printing too cold and/or too fast for the required amount of filament to properly melt and be extruded?

In my UM2 (non-plus) the thick light brown blobs and burn marks come from material accumulating on the outside of the nozzle. Then this sags and gets deposited somewhere on the print, and then gets smeared out. These often appear when there is a bit of overextrusion, for example if the layer contains lots of short infill lines where the head has to slow down and change direction. Little, thin black flakes come from the inside of the nozzle, and they often appear after a cold start, thus in the beginning of a print. If I carefully watch while printing, I can see it happen. Some materials and some colors are more susceptible to this than others.

Yes you are right. Thanks for the correction, I appreciate it. Abbreviations are not my strongest point... :) That said, both could cause problems: when my cell phone is laying next to the computer and it rings, this often locks up my USB mouse and keyboard (in addition to causing flickering in the screen). Then I have to unplug both and plug them in again. So I can imagine that similar things could happen in a 3D-printer.

If the environment is already 35°C, could it be that the filament starts softening? Or that the heat transferred from the feeder stepper motor to the feeder wheel is just too much, and it softens there? Maybe you could let a fan blow onto the feeder too?

Concerning ESD: maybe you could try to discharge yourself before touching the printer, for example by touching a metal plate connected to earth, or by wearing an electrostatic safety wrist band? I had a couple of times that the display and rotating button of my UM2 got locked up when simply touching the frame of the printer. This was in winter when it was very dry, and when I was causing huge sparks when touching anything. And even in calm residential environments, you could have lots of ESD sources. Think of computers, 230V LED lamps, cell phones, wireless phones, wifi, TL-lamps, airco or fridge motors, solar panel converters,... Especially cell phones: try keeping them far away from everything else.

It may just be material-dependent, if the molten material is very sticky like hot-melt glue. I have this on my UM2 too with PET, but far less with PLA. Printing much slower and cooler helped a bit, but did not eliminate the effect in my tests. Especially the slow printing helped, since that gives less pressure in the nozzle, and thus less overextrusion on short lines when the printhead hast to slow down. PLA melts into a sort of yoghurt-like consistency which is easily deposited on the print, but that particular PET melts into a sticky elastic glue, which retracts into a ball and keeps building-up on the nozzle. I would suggest: try printing a little test block (e.g. 15mm x 15mm x 15mm), 100% filled, and on the fly adjust printing speed and temp, and keep watching. For my PET, printing at 25mm/s, 0.1mm layer heigt, and 220°C seems to work best (=at the lower end of the recommended range of 215...250°C).

If you like the simple push-pull user-interface and workflow of SketchUp, I would suggest you take a look at DesignSpark Mechanical. That has a similar push-pull style of user-interface, is easy to learn, and it is also free (only requires registration). In 3 years time it never gave me any STL-problems. In Youtube, have a look at the various demo-films to see if it appeals to you. There are also good tutorial vids.

@SteveCox3D and @SandervG: I think SteveCox3D saw this thread as one long list of proven design tips for 3D-printing in general, thus for all sorts of purposes: strength, ease of printing, good overhangs, ease of post-processing, etc... For which he wanted to add more tips in the future (I am looking forward to that). Thus similar to Cloakfiend's long thread on acetone smoothing, which contains almost everything we know about that subject. If this assumption is correct, then I think it is best to keep this in one long thread. If no (thus if he prefers to focus on one topic only), then it might be better to split, since I don't want to hijack the thread. My personal preference would be to keep all design tips in one long thread, where everyone can add tips and images. But I would like to leave the final decision to SteveCox himself, as starter of the topic.