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Everything posted by geert_2

  1. Up till now PET has survived undamaged and unwarped in my car, even in our recent very hot summers with Mediteranean weather, quite unusual for Belgium. Contrary to PLA that even did not survive a mild spring or autumn sun. I think PET can have around 80°C? If you would need it for autoclaving and desinfecting at 140°C, that would be a different story.
  2. Excellent info from p-kimberley above. What is said, is absolutely true: any layer lines, blobs or irregularities will show up in the cast, and they will make it *much* more difficult to remove the cast from the mould. I have made silicone moulds from 3D-printed models. It goes as follows: first 3D-print a model, including what will become the filling canals and venting holes. Print in multiple parts and assemble as required. Carefully remove all blobs and irregularities, and smooth the model, as any defects will show up. Stick the model to a plastic base plate, or provide some for
  3. Maybe you could do it with a trick? Put four tiny dots outside of each corner of your models. So that they form an imaginary rectangle that encloses your design. Or draw a custom skirt around your design; just one layer height is sufficient. Then that surrounding skirt or border should always be placed in the same position on an empty bed. Keep that skirt, or those four dots, in place, and then correctly place the rest of your components in this space, and save as separate files. When slicing, the skirt (or the four dots) should determine the position on the glass. At least, that is what I wou
  4. The cones were printed on my UM2 printers (orange on printer nr.1, white on printer nr.2), several years ago. As far as I remember, they all have 0.1mm layer height, but they may have been printed at different speeds, flows and temperatures (I don't remember). The main goal at that time was to see the effect of using a dummy tower (=the square tower) to increase cooling time of fine details. Otherwise the hot nozzle stays on top of the model, so it can not cool down and solidify. I have the other model printed as well, but I don't have photos. I will see next week (too dark here no
  5. How do they handle bending loads, and impacts such as hitting stones on the beach?
  6. Now it looks a bit like those chocolate coins wrapped in silver paper, that we used to get for Santa Claus. Isn't there a way to make the plating chemically bond to the print? Somehow etch and chemically activate the outer layer? Or plate a first layer with a mix of glue and metal, or something along these lines? How do they do this for plastic car "chrome" strips, wheels and radiator covers?
  7. Maybe you could consider this: make a test design that includes all your typical problem areas. For example: long flat bars (do they bend?), thin pilars (smooth, stable?), steep overhangs, small holes (size?), smooth curves (layer lines?), fine text, watermarks, sharp corners (ringing, rounded?), thin plates, or whatever else is typical for your designs. But keep it relatively small so it prints fast enough. And then have that test model printed at: (1) the printers best quality, (2) default quality (well balanced between speed and quality), and (3) fastest draft quality. Of course
  8. To me the second photo looks like overextrusion in general. Then molten material is likely to accumulate on the outside of the nozzle, after some time it gets burned, sags, and then gets deposited on the print in ugly brown blobs. Happens easily with PET, but I have also seen it with PLA. Watch closely while printing: it will be well visible if this is the case indeed. Printing slow and cool generally improves this in my prints (on UM2). But I don't mind some overextrusion in the first layers (=nozzle too close to glass), because that gives shiny flat undersides and good bonding.
  9. I just think about this: if you live in Belgium, the Netherlands or West Germany: we have an independant and quite good distributor of 3D-printers from various brands and various technologies: the company Trideus, in the province of Limburg, Belgium. It might be a good idea to go to such a distributor, have a look at their demo-prints, have a talk and ask prices. Since they have lots of brands, they are likely to give more honest info. For them it is not so much the brand that counts (they have almost all), but if the customer is satisfied enough to come back next time. So you are more likely
  10. Depending on what "small quantities" are, and on the variations in your models (all identical or not), you could also consider low-cost injection moulding in aluminum moulds. For example at companies like Protolabs, or maybe also Materialise. Then you have a more professional look and sturdier models without layer lines that can initiate cracks. Low volume production is their specialty. You can submit a design and get an online quote. If you need only 10 parts, or if you need variations in models, this might not be worth it, but if you need 100 or 1000 identical parts, it might be?
  11. As an alternative, you could always design your own custom brims and supports in CAD. And then switch them off in Cura. This can be usefull for complex shapes or special requirements, for example if you need way more brim on one side, but not on the other side, or if the brim needs to have a special shape to get in with tools to make it easier to remove.
  12. Nice, looks a bit like the old English coins I once had. You used an interesting support-strategy here. Did you do this with a single nozzle, or did you use PVA supports also? How did that bottom area come out, concerning sagging and curling up? In the next batch, could you make a close-up of that, before post-processing?
  13. In the older Cura-versions there was a setting "Combing" or something similar, which did exactly this: then the head would keep on already printed material, avoiding voids. I don't know about the most recent versions. Have you searched for that? However, this will not prevent blobs in some materials (the PET that I have): material is accumulated on the nozzle during printing, and then it sags and is deposited on the print in a thick blob. If this happens near the edge, is will spread outwards. So you have to post-process anyway with some materials.
  14. Maybe try pushing down the white ring with a suitable size hex wrench, or a ring or similar, so the load is distributed evenly on the ring? And then gently first push and then pull on the tube, and wiggle a bit? But always relatively gently. No brute force?
  15. To make removal of the clips easier, you could use these, or design a similar one yourself. Then it is piece of cake. For the model, see here (and then scroll down a bit): https://www.uantwerpen.be/nl/personeel/geert-keteleer/manuals/ In my own machines, I have a new design that is a bit optimised, but I haven't uploaded it yet. But I used these for 3 years; and they are reasonably good.
  16. That is nice. I could imagina this used for making emergency chalets, containers, caravans and other mobile homes. Lots of great application possibilities. How is water-tightness? (Important for boats and houses) I would like to see the boat in the water in real use. And how layer-bonding and strength, especially impactstrength? And resistance to sagging/deformation when the model is placed on uneven grounds? And how is the "filament" melted? Or do you use pellets, or liquids? I think a system with fast-curing composites with integrated mixing ti
  17. Or you could design and print your own custom low-friction spool holder, for mounting on the back of the machine. My design will not fit your spools (it is for single standard spools only), but you are free to borrow and adapt the concept. It uses one standard 608 bearing (=also used for skater wheels). Design-files are in the rsdoc-format (=native DesignSpark Mechanical format), so if you have DSM you can edit them. Be sure to make it much stronger to support a large heavy spool. I also have an anti-unwind clamp that freely slides around the edge of colorFabb spools, to prevent th
  18. On my UM2 (single nozzle) printing in thicker layers reduces this effect quite a lot. But then of course you have more visible layer lines. So it depends on whether your application can have this. Maybe you could design a small test piece, but not too small so it still has enough cooling. And try printing that with different layer heights, orientations (for testing cooling flow), temperatures and speeds?
  19. For the spool holder with integrated balance: near the end of an old spool of stiff PLA, it may take 1kg (10N) to unload filament, to overcome the "spring effect" trying to wind it up again. Sometimes I can lift a nearly empty spool by the filament, without it unwinding. So, depending on the orientation of the pulling force, this might introduce quite big measuring errors, I think? This would especially be a problem where accuracy of the remaining length matters most: at the end of the spool. But at least this system provides a simple linear conversion between weight and remaining length, once
  20. I think they are going to be too stiff. And blobs, irregularities and print lines are not going to help making it water-tight. Unless you would squeeze it extremely hard between thick steel flanges. If you don't want to store gaskets, or originals can not be found anymore, I think you would be better off cutting new gaskets from a sheet, with a knife or a Dremel tool? Or use self-curing silicone or similar paste? For comparison: transparent PVC tubing for aquariums is much softer than TPU. But when I tried to use that recently to make a seal for my water-cooled disk grinder, I had
  21. The thing is that a lot of spools are not transparent. They only have a small window, and they *do rotate*, and so does that window. So you can not see nor measure from the axial side how much filament there is still left on the spool. You would have to measure radially, thus from the top (sort of), and then calculated differences in distance by means of the reflected light, similar to a radar. And then calculate radiusses and circumferences for each winding, and the amount of windings. And then things soon start to get very complex. When you have spools that are very loosely wound, or materia
  22. I guess redesigning it to make it smaller is not an option, as probably some elektronics have to fit in? I would consider printing it in two parts, flat on the glass. But then it might be a good idea to have some overlapping areas in the side walls, if the design allows for it, so you can glue it better. See the pic below for the concept. Another option might be to print it diagonally on its side, from front left to back right, instead of slanted vertically? Then you only have to provide supports the top edge that is overhanging, and the bosses. To mi
  23. Multiple lines of skirt (=an outline around the model, but a few mm away from it) do solve the underextrusion due to the oozing before printing. I usually do between 3 and 10 lines of skirt, depending on the size of the prints: the most for small prints, the least for larger prints. I don't have problems getting them to stick, even if the beginning stutters a bit. Also, it gives you the opportunity to check if your bed leveling is okay, and it purges the nozzle and removes some of the dirt in the nozzle that often comes loose when starting a new print (=tiny black flakes in the mel
  24. Have you tried blowing the readers out with compressed air? Quite often there are dust and hairs accumulated in the slots, causing bad contacts between the cards and slot. This has helped several times for me. Do the printers fail on all cards, or on only one or two cards (but in all printers)? You could also have a bad SD-card, or a bad batch of SD-cards. Or you could have a program that has corrupted the cards. Or accidental corruption due to power loss or removing the card while writing to it. That sort of things. I am not saying these are the solutions (you may have
  25. I think so, otherwise the problem should have moved with the glass. So it must be or a bent bed, or incorrect leveling, or both? If you would have a steel ruler or a steel bar that is totally straight, maybe you can put that on the bed, and see if it gives perfect contact everywhere? Or does light shine under it in certain areas?
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