Yes, its a goo idea. To get over peteredworthy's bending issue simply add some webs (although this will be a compromise to clear the belt wheel and belt). A compromise would simply to mount the build table and current brackets upside-down. THis would need the support nut/backlash spring reversing. Also, is there any reason why the Z pulleys&belt cant be moved up to the top of the M8 studdinby Lampbus - Mechanics
Forrest, lots of wire wrap in the 70s - I had an IBM system/34 'minicomputer' that had wire wrapping all over the backplane cards that the CPU(s) where plugged into. As you say, not good for HF but probably v good as a replacement for and etched PCB and saves mucking about with hot metal alloys in channels but Im sure they have a place in replication too)by Lampbus - Plastic Extruder Working Group
I just had an idea (please tell me if it is original or not) : Why not use copper wire despensed from a reel, through an auto-chopping head and onto reprapped posts? (and IC legs, component legs etc). A PCB has milled/etched copper to make connections & a rigid insulator to mechanically support the components & connections. THe FFF forms the board (forget double sided - you have 3 wholeby Lampbus - Plastic Extruder Working Group
I am working on an alternative feeder design - described elswhere on this forum. Its good to have some pressure data I have HDPE on order so it looks like I will start tests there. The bowden cable (bike brake) idea is interesting. My Brother did some calcualtions when we were re-designing our car's handbrake arrangement - avoid bends at all costs - massive friction occurs. Of course these areby Lampbus - Mechanics
My design just made another little leap - Mk1 will use mini flanged ball bearings in each roller end to take the radial & axial thrust. 3 quid each from RS, but probably half that from my bearing supplier. I could use one in each end but a simple bush will be ok at the lower ends. Shaft reduces to 4mm which saves space and a smaller set of circlips can be used, which helps with the main cageby Lampbus - Controllers
I am currently working on a tripple roller feeder. The three knurled rollers are carried in a cage which rotates around the filament. The rollers are angled at 5 degrees from the filament axis to give approx 1mm/rev advance. Pressure is applied by a set of circlips pressing in on the roller shafts. I am currently working out the best way to mount the cage on a bearing to withstand the axial thruby Lampbus - Controllers
Waterjet is wet, noisy, slow and abrasive particles get everywhere. I used it for cutting brake lining material (copper loaded etc and not laser friendly). Its great for cutting graniteby Lampbus - RepLab Working Group
There is a problem with heating the melt in a pot - when you pressurise it to blow it out, it may well form rat-holes - a comon in viscious and powdery product where a small section flows out leaving most of the rest just sitting there. The solution is a 'follower plate' which seperates the pressurising air and apples the pressure accross the whole of the plastic surface. Like an air pushed syrinby Lampbus - Mechanics
It is also known as plastic welding CORD. I dont know how that translates into Portugese though. I assume rod is usually associated with thicker, rigid fixed lenghts of stuff.by Lampbus - Reprappers
Quadrature is unlikely because it is attached to a motor - and the printer knows wich way it is running the motor, just not how fast. (speed varies with load, direction (usually) dosnt) Quadrature is only useful where the controller dosnt control the speed or direction. Like in a mouse.by Lampbus - Controllers
Great idea.I assume they are in silicon which should be able to manage the temperature. If the plastic sets, it should all melt again when the heater is on. They should be an almost disposable part.by Lampbus - Mechanics
Its called closed loop control. Steppers are open loop - the controller powers the coils in the new pattern and you hope there is enough torque (torque=twisting force) to move the motor to the required position before the next step. If there isnt then you miss steps and never know and will be out of position. Obviously design all the parts to be powerful enough. Servo control is closed loop - tby Lampbus - Controllers
Kyle - thats why it is a window and not a hole. Made from material that is optically clear to the laser light in use but rigid enough to withstand the extrusion pressure.by Lampbus - Plastic Extruder Working Group
The idea that I could scan my foot and make a boot to fit is an interesting idea. You could scan your shin for perfect shin pads. 'personalised' cricket boxes anyone ?by Lampbus - Let's design something! (I've got an idea ...)
well, I was thinking along the lines of anti-ooze - freezing a plug of plastic in the nozzle as a valve, and sorta switched it round - drop on demand. The whole dispense head will be smaller and lighter - higher acceleration & more precision from a lighter, cheaper chassis + motors. The nozzle will be much closer to the XY assembly so thermal expansion in Z will be insignifcant (currently tby Lampbus - Plastic Extruder Working Group
Ive just got my ski boots out of their bag and had a look - the main shell is marked as . Has anyone tried to extrude thermoplastic polyurethane ? It is available in welding cord form @3mm from a quick google. Is this stuff anything special? What is a non-thermoplastic polurethane - a 2 part mix&cure?by Lampbus - Let's design something! (I've got an idea ...)
Ok, so first part of the cycle, you connect your compressor as a vac pump. THis expands all the bubbles and makes them rise & burst out. I still think it needs some simple version of existing plastic extrusion technology - lets not re-invent the wheel here. (ok, im the clever one - I know exactly how it should be ..... paint it blue)by Lampbus - Mechanics
Yes, you could. But do you want to ? Lots of people in engineering still use CNC plasma cutting over CNC laser cutting. Plasma cutting is rough, wide cuts with inferiour edge finish and taper, but it is FAST and CHEAP and for larger structures in particular it is the best option. It is the same with RepRap. What do you want to do with it ?by Lampbus - General
With all the talk of lasers for cuting or polymerising or selective sintering, I had another use for them : Replacement of the heater barrel. Would it be practical to feed the filament as in Darwin, into an insulator barrel with a window in the side just above the nozzle. Use a laser or similar energy source to DIRECTLY heat the polymer to melt. It may even be possible to eliminate anti-ooze vaby Lampbus - Plastic Extruder Working Group
Now if we were to extrude a wall around our part as we build it (using the current edarwin extruder etc) and fill the area inside the wall with HOT waterfrom a pipe in the z platform - the built layers would be kept warm to reduce warping. This is like keeping the whole machine in a hot air oven but better. (or wetter). Keeping the water level below the top may be tricky - wasnt someone workig oby Lampbus - Mechanics
Very fascinating. I googled some stuff - up popped a ski forum posting by a chap I know who is a ski boot guru. I must drop him an email. Edt; On the internet he's known as 'smallzookeper' for esoteric reasons I never quite got to the bottom of.by Lampbus - Let's design something! (I've got an idea ...)
I 'built' a david laser scanner - downloaded the software, printed the backdrop, found a bit of perspex bar to turn my laser pointer into a laser fan. I had a quick try and it seemed to work, but I used the smaller backdrop print and the laser is a bit wide (but I dont know if that matters) and my cam is very low rez so the resulting scan was a bit rough. But it worked. Hmmmm. I could hook upby Lampbus - 3D Scanners, Book Scanners, and Optics
Ralith : A bit of googling found But I dont have time to read it ATM.by Lampbus - RepRap Host
Ru, actually, this is an interesting point. Have you seen wildcat ? the author proposed generating slices from his software. I assume the slices could end up with nice b-spline edges. Are there G codes for those? hmm. Would be nice though.by Lampbus - RepRap Host
I have to agree with Forrest, the early days of DTP vs command driven or embeded code stuff that profesional typesetters use, was is sorta where we are now. Early DTP was realy bad, but look where the software is now. Remember clip art libraries? I always avoided them, and I dont intrract enough with the corporate world to know, but I suspect it never took off in the way original developers thoby Lampbus - RepRap Host
THere may be a strength issue. Idont know what plastic they are made from, but it would need a good low temperature performance. I have heard of a (older) boot line that would shatter. Of course, this is the last thing you want at speed (where loads are high) or in the back country where exposure kills. I totally broke my ACL knee ligament in a high speed incident - the binding didnt release butby Lampbus - Let's design something! (I've got an idea ...)
ANdy : (Ignore oddsnsods, it appears to be a worksheet not finished parts) the parts are not quite finished. I would say they need : Base and Bottom = ok. The base is the Z platform - guided by two vertical rods and lifted by 4 screws as Darwin. Top = error in the location of one of the tags (bottom left). Note this carries the Z motor. Short sides (in the same file as long sides) = need workby Lampbus - Laser Cutter Working Group
Dylan, I was thinking of enclosing my repstrap too, basically because commercial machines do to keep the build warm. (and to keep my cat out) I noticed that the latest laser cut plywood panels have a full box design in place of the Darwin 8mm bars&corners etc. This would be interesting. The problem of sealing the top to keep the heat in & the motors etc in cool air could be solved by hoby Lampbus - Laser Cutter Working Group
No giant bunnies here : but not much else either - but it seems to be a current active project for engineering 3D CAD.by Lampbus - RepRap Host
Peteredworthy - lateral thinking at its best. Actually, series thinking All good thinking. My only concern is what happens to the first sensor whern it effectively looses its ground. It will also probably go high resistance on its outputwhich as you point out is immaterial. However, it now has no power supply so it will possibly not start up again until the second sensor pulls its ground low agby Lampbus - Controllers