Steppers are almost always the last point of failure in a design, even the cheap imports. High quality stepper motors can cost several hundred dollars each.by 691175002 - General
Anyone who claims that microstepping materially decreases motor torque is incorrect. Hobbiysts misunderstood the following chart (confusing incremental torque for stall torque) and the idea has refused to die for years. It is pretty obvious that running 1/16 steps does not reduce your torque by 90% or nobody would do it. Many high-end stepper drivers have a fixed microstep count (Ex: Gecko) wby 691175002 - General
Quotewingmaster If you balance the weight of the 3d printer head with some counter ballast, then the motors on a delta printer would not need to create force to hold up the weights. The only force they have to create is to accelerate and de-accelerate the mass. Sadly the amount of it mass need to move doubles in this case. But because no power is wasted in lifiting weight, all power can do to movby 691175002 - Developers
Cost isn't really a great way to compare 8 vs 32 bit. Modern boards have more features and higher build quality. The 328 is ridiculously expensive for its capabilities and the only reason it is even in production is due to hobbiest demand. Modern 32 bit chips are cheaper and orders of magnitude faster.by 691175002 - Reprappers
If you want to stick with linear shafts I think misumi is a good choice. Their LMU8 bearing is only 6$. I'd recommend getting matching shafts as well since getting optimal performance relies on a fairly close tolerance between the bearings and shaft. For more rigidity I'd consider moving to 12-16mm hollow shaft to keep the weight down. Obviously the nuclear solution is to go to linear block aby 691175002 - Reprappers
Quotethetazzbot I haven't figured out how to use their cad parts in Solid Works yet They offer downloads in solidworks format. It comes as a macro file that you need to run. They do this because .sldprt files are not compatible between versions, but macros are. Sometimes it is easier to download just the dxf cross section and extrude it yourself so you don't need to download the same part inby 691175002 - Reprappers
I love Misumi. They are cheap (for some products), fast, good service, etc... They even gave every new customer 150$ in store credit, no strings attached a while back. That was just crazy. About the only bad thing I can say is that their webpage can be confusing, and their products are ridiculously configurable which makes things even more confusing. Once you figure it out you can get accuraby 691175002 - Reprappers
One thing people seem to forget is that once you start counting microns a 3d printer really isn't that rigid. If your nozzle is too close to the previous layer the plastic will both push the nozzle upwards and spread out more, making it somewhat self correcting. Once your layer height gets small enough you basically need to imagine every linkage as a spring. The hotend in most printers will moby 691175002 - General
QuoteAndrewBCN Indeed, 3 to 6 months... and what will you be using to drive your PLA filament, a Greg's Wade's geared extruder? LOL! Linear servos are actually great for 3d printing if you ignore their astronomical cost and complexity. I'll admit its a pretty silly idea. I found the linear stages on ebay and the auction was so cheap I couldn't help myself. After they arrived I had to come upby 691175002 - Developers
Quotefrankvdh AliExpress is your friend when it comes to supplies and prices... 12V linear motors start about $21 for 200mm/1000N. There's no reason you couldn't have a hybrid... a stepper for the vertical axis (which doesn't move much or fast), and linears for X,Y. A motor glued to a screw is a linear actuator, not a linear motor. Aliexpress does not have any true linear motors for sale. I aby 691175002 - Developers
The high accelerations of a servo are only viable because their average power draw is so low (allowing high peak currents). If you are constantly at 50%+ duty cycle to fight gravity your maximum acceleration will be very poor, especially if you want to go up. This isn't as much of a problem for regular servos since the rotor inertia is pre-reduction. Do you have examples of linear induction moby 691175002 - Developers
Linear motors are not well suited to DIY or to delta printers for several reasons. Linear motors require pneumatics in vertical applications since they provide no resistance to motion when unpowered and fighting gravity is an enormous waste of power. DIY is not an option. Getting accurate positioning from a motor is difficult - you need to use a lot of tricks to avoid cogging (ironless motorby 691175002 - Developers
Acceleration is actually far more important than velocity for print speed. You need a long straight movement to reach a printers top speed, and that will almost never happen during infill and typical slicer paths. Sure, you can type 700mm/s into the config file but that doesn't mean your printer is ever going to reach that speed. See this guy for an example: Positioning at these speeds is aby 691175002 - General
I think it makes more sense to work around the limitations of bowden. It is more flexible and scales in number of extruders very well. I think an encoder on the hot end to compensate for hysteresis could overcome most of the drawbacks. Adding an encoder is also a fairly straightforward project compared to building a linkage that is reliable under high acceleration and temperatures. Any mechanby 691175002 - Developers
The bed shape of a delta just isn't great for some requirements. It's much easier to make use of a square or rectangular bed, and if you are printing brackets and other functional components height isn't as important. Also the build volume as a percentage of overall printer volume is much higher for a fixed or z-bed cartesian printer.by 691175002 - General
I never understood the ubiquity of CoreXY designs among hobbyists. It is an inferior derivative of the H-bot belt path. No commercial systems use CoreXY. H-bot is the standard for high speed cartesian positioning. Stratasys uses an H-bot belt path in the majority of their printers. Many laser cutters use an H-bot belt path. CoreXY is a hack to compensate for poor frame rigidity by twisting aby 691175002 - General
Here is Misumi's data. The pictures show how each tolerance is measured. I'd use a feeler gauge on a glass table, I suspect most countertops/desks will be less flat than the extrusion. Technically a dial gauge will measure the width/height of the extrusion as well as its straightness so you may overestimate the error. As I mentioned, the official tolerances are awful but in practice they seby 691175002 - General
They are solving a non-existent problem. What shortcomings of existing extruders are they attempting to fix? Do they find the current generation of extruders to be unreliable? Are extruders limited by cooling? Watercooling is problematic because flexing the hose continuously for months or years of use is not a great idea. Do you really want to have to rip up the loop as part of preventativeby 691175002 - General
Extrusions are not designed to be straight, and the tolerances are really ugly. Misumi allows up to 4mm of bend in addition to seven degrees of twist per 1m length of extrusion. In practice you will probably never receive a piece that bad. I'm not a fan of using extrusion for linear motion because linear shaft and bearings are so cheap. Why bother with extrusion when the correct components arby 691175002 - General
Generally a similarly sized stepper motor that has higher torque will also have a lower top speed. You can see it on the datasheet as higher inductance.by 691175002 - General
I've used stepper/lead-screw combination and was pretty happy. They are slightly more rigid/concentric since you can skip the coupler. I'm pretty sure that whether you buy the combined stepper/screw or separate pieces they are all coming from the same factory. I think they are unpopular since they are awkward to ship and more expensive than separate components.by 691175002 - Reprappers
These problems have all been solved centuries ago by machinists. All you need is a dial indicator. Squareness is also easy to measure, but more expensive since most squares with <0.001"/ft accuracy costs 200$+. The biggest problem you will run into is that the printer flexes too much to get a reliable reading. If you measure with enough resolution pretty much everything flops around, especiby 691175002 - General
For applications that reverse you often see two set screws stacked into the same hole. The second set screw is tightened onto the first to prevent it from backing out. It sounds kind of wonky but works very well. It is also incredibly frustrating if you are trying to disassemble it and don't realize that there are two set screws.by 691175002 - General
Any opinions on the XL vs the lite version? Does the gearbox provide any advantage for pushing 1.75mm through a bowden?by 691175002 - General
A fully autonomous postal system will be so cheap, fast, and efficient that there will be no need for people to have their own 3d printers. You will upload files to amazon.com and the part will get dropped off minutes or hours later. Its pointless for every household to own a printer when they will spend 99% of their time idle. Sharing a few extremely advanced machines (multimaterial, high quaby 691175002 - General
QuotenopheadThe way to go is probably a brush-less DC servo motor at the fixed end of the Bowden tube and a shaft encoder and pinch wheel at the entrance to the hot end with closed loop control. No need for a servo, just use a stepper as normal. A servo would require dual encoders to be stable.by 691175002 - General
QuoteA common misconception about printing with high flow rates is that 3mm filament is going to be better than 1.75mm. This makes intuitive sense, larger prints so use larger filament. However in reality 1.75mm filament can be melted significantly faster than 3mm filament, giving it a decisive advantage in flow rate. This is because 1.75mm filament has a much higher surface area per unit volume.by 691175002 - General
The tool chains are pretty much identical the only difference is what software you use to generate the G-code. For a 3d printer you use slicing software, for machining you use CAM software. G-Code is a universal standard, there will be no compatibility issues*. Almost all 3d printer controllers have milling features, GRBL for example has spindle control commands and Smoothieboard is explicitlyby 691175002 - General
Scaling up printer designs isn't really that hard, it just requires a different approach. The real challenge is extruding plastic fast enough. Hobbyists regularly build 8'x4' routers that can hold within 0.010" fairly easily. I'd recommend an H-Bot using timing belts ( ). I'm not a huge fan of CoreXY in a build that uses linear block and rail (which you should be using). Alignment isn't thaby 691175002 - General
That is actually pretty awesome. I think it has a lot of potential now that people are starting to looking into printing as fast as possible. Once we start looking into things like temperature catchup or feedforward in the control loop, getting fast response at the nozzle will be very important. What we really need next is a way of measuring the extrusion temperature as closely as possible soby 691175002 - Developers