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Re: precision positioning needed for shifting the position of lenses - 6 years ago
The motors will stay synchronized while they are powered, but they can be independently rotated by hand when un-powered. This is typically only a problem if alignment through many on-off cycles is important (such as the Z axis of a 3d printer). The easiest situation for you would be if the exact starting alignment of the lens does not matter, because then it doesn't matter if the linear stageby 691175002 - Mechanics
Re: precision positioning needed for shifting the position of lenses - 6 years ago
I didn't see the speed requirement in you original post, so re-purposing a translation stage would probably be too slow regardless. A quick look at the math from datasheets of a similar cd motor (http://robocup.idi.ntnu.no/wiki/images/c/c6/PL15S020.pdf) suggests that they will work. I would recommend using a pair of actuators for each axis so that you get twice the torque and can also use themby 691175002 - Mechanics
Re: X and Y counterweight? - 6 years ago
Srek pretty much covered it here: QuoteWhile you can compensate the implus with this you double the amount of torque needed to accelerate. So yes, it can create smoother movement, at the same time you need stronger motors and more power as well as stronger belts. Adding mass to the frame is generally much cheaper than doubling your motor torque, so counterweights are rarely used. Printers are aby 691175002 - Mechanics
Re: precision positioning needed for shifting the position of lenses - 6 years ago
Your existing part choices are not too inspiring, typically optics require very precise positioning. I generally approach this kind of task by purchasing a manually adjustable mount and slipping timing pulleys over the knobs. It will takes about 15 minutes to design a printable assembly that can hold the lens mount and two stepper motors together. The advantage of this is that its easy, much cby 691175002 - Mechanics
Re: Can anyone give advice on Linear rail preloading? - 6 years ago
You want V0. Preload doesn't make sense on a belt driven axis. Even VC would be more appropriate than V1 because any resistance to motion will degrade motion in the timing belt, motors, and frame. Even at VC, 13um of play in the rail (averaged across 2 rails and 4 blocks?) is basically irrelevant. Timing belts will deflect more than 13um if you blow on them. You might also consider one of thby 691175002 - Reprappers
Re: Urgent advice needed on warped ball screw! - 6 years ago
Slightly bent ball-screws are a somewhat common occurrence. It is not normally an issue In CNC milling machines and routers because the surrounding components are rigid. You can straighten screws fairly easily with the correct tools. Some cloths, v-blocks, and an arbor press is the best option. Otherwise a vise plus a cheater bar (aluminum tube to go over the screw and use as leverage) does okby 691175002 - Reprappers
Re: Linear electric motors, and high speed printing in general - 7 years ago
The videos here have audio: The baseline ambient noise is a low-rpm 120mm fan, and the servos are barely audible above that. There is a very mild hum at rest which gets overpowered by the bearings and other moving parts in motion. I would describe the servos as mostly silent.by 691175002 - Developers
Re: Hotend design question - 7 years ago
The limiting factor when melting plastic is the time it takes heat to penetrate to the center of the filament. Moving the heat cartridge closer (or even into) the bore doesn't really change anything, because the filament was already in contact with hot metal to begin with. You want even heat from every side, not a single small hot spot which will not have time to diffuse through the filament.by 691175002 - General
Re: Please help me to pick the right electronics package. - 7 years ago
Size 25 rail mixed with Nema17 motors and 6mm belts don't seem like an appropriate combination. Linear motion components should be of similar performance because in a general sense you will be limited by the weakest link (including pulley/idler mounts, and belt tension). You should drop down two rail sizes or raise the rigidity of the other linear motion components. Its more of an aesthetic crby 691175002 - General
Re: Linear electric motors, and high speed printing in general - 7 years ago
I've been working on a blog but the updates have been quite sporadic. Eventually I'll review all the posts and turn it into a proper build log. I browsed your site and actually found the printed bellows to be very interesting, as in my experience custom bellows tend to be expensive and hard to source. Lasers are fun but I hope to never find myself in a situation where an interferometer is neby 691175002 - Developers
Re: Mini Mills, Bench Mills. Cutting aluminum extrusions square. - 7 years ago
I always recommend taking a look at the g0704 mill because it is so popular. It sits at at price/performance sweet spot, and there is a ton of support for it. The mill you linked will also be fine. I wouldn't go as small as a micromill since you will want to use endmills long enough to clean up 4040 without flipping it over. The main drawback of machining is that accessories (cutting tools, woby 691175002 - General
Re: Linear electric motors, and high speed printing in general - 7 years ago
I also come from a CNC background so I agree with you completely. Sometimes I joke that I've spent more on metrology than machine tools. Unfortunately the FDM process is probably too slow and sloppy to make use of the performance linear servos can achieve. I hope that I can print somewhat faster than average while also producing surface finishes that are slightly better than average, but I'm nby 691175002 - Developers
Re: Linear electric motors, and high speed printing in general - 7 years ago
Quotejanbbeck That is beautiful work! I am working on a similar system: How did you do your sheet metal? On cooling, have you looked into the Berd-Air? The guys on the Zesty Nimble group say very good things about it. Nice project, the Granite Devices drives are a neat touch. I'm using VIX-IH drives, but those things must be twenty years old and there is no way to monitor the position/errorby 691175002 - Developers
Re: Linear electric motors, and high speed printing in general - 7 years ago
I've been making slow progress. The current problem is that the Aliexpress extruders were producing waves in their output. Probably a bad batch of steppers or bad hobb geometry. I decided to redesign the whole assembly with E3D titans because they have more resolution and are lighter as well. It will also need very good layer cooling, which is kind of a PITA to route to a Chimera sinceby 691175002 - Developers
Re: Has anyone tried using carbon fiber tube for the X axis? - 7 years ago
I know that carbon fiber sometimes shows up in pick and place machines, but it seems to have fallen out of favor. These days an epoxy granite base seems to be the trendy thing to do. My guess is that when you consider the weight of the entire axis, switching to carbon fiber just doesn't make enough of a difference. I could see it helping for a 3d printer but I think you will be chasing marginaby 691175002 - Reprappers
Re: Choice of linear rail size - what to pick! - 7 years ago
I'd probably go with HGR15 or 20 for YZ and MGN12 for X. Your printer is large enough that you want to be getting most of the rigidity from the extrusion that the rail is being bolted to, as an aluminium tube is stiffer per gram of weight than a solid bar of steel. You should reconsider making the X axis the long axis. As a general rule you want the moving axis to be as short as possible. Tecby 691175002 - Reprappers
Re: Heavy 15Kg bed + ball screws = problems with Z axis motor holding? - 7 years ago
QuoteSplatHammerA poster on another thread wrote as if the brake could be engaged by the software after lowering the bed a step. I was dubious so thanks for confirming my suspicions! : ) Sometimes a break will engage/disengage during regular operation but such cases are rare. The main situation where you will see this is when you want to lock the axis and then apply extreme forces that would ovby 691175002 - Reprappers
Re: Heavy 15Kg bed + ball screws = problems with Z axis motor holding? - 7 years ago
If a motor is capable of lifting the bed it will have no problem holding it in place. Brakes are used when the axis will back-drive without power. The brake is designed to close automatically when the machine loses power so that the axis doesn't fall to the bottom of its travel every time you turn the device off. A brake will not improve performance while the printer is operating, and honestlyby 691175002 - Reprappers
Re: Nema 17 motors from Mcmaster-Carr. Are they worth it? - 7 years ago
No. McMaster will provide high quality components, but they tend to mark that kind of low-volume stuff up tremendously. They don't list the brand you will be receiving on their webpage so you cannot perform a cost comparison - but if you were to order a stepper motor from them I am confident that you would find they charge 60-100% above more direct suppliers. If you want a quality stepper motoby 691175002 - General
Re: Bondtech Extruder Patented? - 7 years ago
I'm not a patent expert, but I suspect there is just way too much prior art. Pushing a tube or rod with a pair of wheels is extremely obvious and you can find such arrangements everywheree. Mig welders, for example, use a virtually identical mechanism to push metal wire through a bowden tube where it can be melted onto the workpiece (sound familiar?).by 691175002 - General
Re: Power supply voltage ? - 7 years ago
Do you trust your multi-meter? The switching LED supplies should have trimpots for adjustment. 11V will probably reduce your bed heating power by a notable amount.by 691175002 - General
Re: Experiences with building and using the E3D Titan extruder (Bowden) - 7 years ago
I suspect you got a defective bearing to begin with, but I recommend being very careful when tightening the screw that goes through the large gear. If you over-tighten it the bearings will be destroyed. A very approximate calculation suggests the bearings can sustain 10Kg of static load while a fully tightened M3 screw can apply around 400Kg of force.by 691175002 - Reprappers
Re: searching GNU CNC Gcode generator - 7 years ago
QuoteTraumflugBelieve me, I've done this hundreds of times and never needed a tool changer or "responsive" jogging or cutter compensation or length offset or whatever reasons you try to find here for keeping people away from milling. My intention is not to keep people away from milling, it just doesn't make sense to recommend 3d printer electronics for milling when there are alternatives which aby 691175002 - General
Re: searching GNU CNC Gcode generator - 7 years ago
QuoteTraumflugI thought we were talking about milling here. Machines coming with a tool changer (what a luxury) most likely have a firmware already, no need to replace that one. At the hobby level you still toolchange since machining with one cutter isn't a ton of fun. Generally the program will pause and raise the spindle so you can manually swap the tool. If your toolholders repeat in Z youby 691175002 - General
Re: Unpluggable Hotend - 7 years ago
I've used other Chainflex cables but not 884 in particular. Flex-rated cables can be a bit of a PITA to terminate because there are so many layers of insulation and shielding to get through (and in most cases you want the drain and shield intact). You also have to remember that even though they are designed for bending, cables with a large number of conductors still need a lot of room. For exaby 691175002 - General
Re: searching GNU CNC Gcode generator - 7 years ago
QuoteTraumflugCNC milling specials like cutter compensation are nice and dandy, but useful for manually written programs, only. I'm thinking more about work offsets, probing (not the z-bed kind), tool tables, etc... CNC without support for toolchange is extremely painful.by 691175002 - General
Re: Unpluggable Hotend - 7 years ago
For what its worth DB9 connectors can be found up to 5A per contact and the mixed varieties can go as high as 50A per contact. I plan on using DB terminated CF884 cable on a future printer. It has perfectly sized bundles for a heater and stepper motor, plus three individually shielded pairs for temp/fans; and the entire thing is double shielded and flex rated. For some reason the CF884 is abby 691175002 - General
Re: searching GNU CNC Gcode generator - 7 years ago
Toolpath generation for subtractive manufacturing is called CAM. There are some open source CAM packages available, but they are quite limited. Be aware that unlike 3d print toolpath generation, CAM is a very complicated process that can cause a lot of expensive damage if done incorrectly. The software is not automatic and requires considerable experience to use. Also note that most 3d printiby 691175002 - General
Re: Control board decision - DuetWifi or Smoothieboard...?? - 7 years ago
QuoteWannaFlyIs this correct? Visualize a stepper motor as having both a magnetic orientation and a shaft orientation. The connection between the magnetic field and the shaft behaves a lot like a spring or rubber band. Just like a spring produces no force unless it is being forced to stretch or compress, a stepper motor is not producing any torque unless the shaft is out of alignment with theby 691175002 - General
Re: Quieter hotend cooling fans? - 7 years ago
I ran across some Ebay deals several years ago and decided to try to build a printer from surplus linear stages. On paper I am capable of moving two direct drive extruders at >5,000mm/s2 and >500mm/s with "perfect" motion quality. The whole concept is senseless overkill but it is also a ton of fun. I'm interested to see exactly what the speed/quality limits of FDM look like when motion iby 691175002 - Reprappers