Quotethe_digital_dentist The problem with schemes that use a switch to detect a head crash is the same that problem that causes the z=0 switch to be ignored. You can't rely on malfunctioning electronics to behave the way you want. The problem with mechanical methods, such as allowing the head to tilt or have a spring(s) to allow the extruder/hot-end or bed to move out of the way is the limitedby realthor - General
Hi guys, just noticed on reddit about the release of a corexy 3d printer called voron and while looking at it it hit me that the XCarriage only uses one LM<#>UU (albeit something Mitsumi, not chinese) per XRod. Even Mitsumi or whatever brand LM<#>UUs have a certain amount of play in the bearings plastic tracks, which would translate to side to side rotation and possibly affect the priby realthor - CoreXY Machines
QuoteVigilant The rods are there to prevent XY, rotational(pitch and yaw) movements to the bed. The thicker it is the better it will resist any force from the Z lead screw other than the Z direction. If you're using belt , then you probably have to worry more on the pitch and Yaw forces. Imagine putting something heavy on just one corner on the bed, will it tilt due to the rods being not stiff enby realthor - CoreXY Machines
Quite complex but nevertheless pretty professional. I am trying on the other hand to make something very simple. Here is a very simple way to constrain laterally (on X) the build plate: Due to the cork the heat should not creep into the ALU angle so an ABS simple part and an M3 allen bolt should do the constraining. I do believe that some sort of insulating pad should be there at the tip of thby realthor - General
Hmm, yeah, not sure what can I take from your setup but I like the levered adjusters (can't see how the thumbwheels do the work there) and also I see you use piezo disks for nozzle contact sensing... or at least this is what I can take from your image. Nice setup though. My setup is quite simple, 3 rods and 3 bearing-blocks that also act as square tube clamps and level adjusters. The issue I facby realthor - General
I kind of made a more realistic (I believe) support, one that involves some aluminum angles and strips of cork for insulation and grip to at least confine the glass/ALU plate to one direction (Y). I am still thinking about how to confine the X axis around the bolts as there is space for it. If you have any suggestions I am all ears I also need to find an angle that is shorter that 12mm on oneby realthor - General
I compared it to the Horizontal XCarriage I have previously designed and I must admit I don't like this as much... the Horizontal is way better (albeit more complicated to print and put together). I'd rather invest more time in refining that one so I'll drop this design.by realthor - CoreXY Machines
@LarsK: How would you "latch on to it" at the bottom? When I was designing the Horizontal XCarriage the only way I have found was to have 4 screws pointing and touching the hotend central column to keep it constrained. But any plastic there will most certainly creep because of heat and any metal there will obstruct air flow from the fan. The more I think about it the more the 4 screws seem to beby realthor - CoreXY Machines
This is 30x30 and is twice as expensive compared to the 20x20 square tube but I don't really see it stronger than the 20x20.by realthor - General
I don't think you gain anything from a Vertical vs Horizontal XRods you are just shifting the printarea (to the front for vertical, and a little to he back for horizontal). The Y bearings have to be set as wide apart in both configurations so yeah... no gain. Z just the same, if you want the least effect of either configuration on the nozzle movement relative to its designated position you want iby realthor - CoreXY Machines
Here's a 30seconds sketch for 1 extruder... I couldn't wrap my head around the 3 extruders ... No time atm.by realthor - CoreXY Machines
The bowden loop has to maintain the largest radius possible to keep low friction between tube and filament. So best approach I see is having the extruder suspended from the bar, just like with a Delta flying extruder so it can swing in all directions, then somehow spring loading the extruder so that when the printhead approaches the position under it, it will rotate around its X axis bringing theby realthor - CoreXY Machines
Hello guys, I have been toying with both Vertical XCarriage and Horizontal XCarriage arrangements and each has its own set of advantages but never both sets in one go. I want my nozzle to be in between XRods and also at the center/middle of the YCarriage and again at the center of the YRods too, to minimize nozzle shifting due to play in bearings, flex in rods, etc. So I am thinking of a horizoby realthor - CoreXY Machines
The Delta style flying extruder approach is the best for this and I can't really see a way around it. You will have to place the extruders in the center of the -supposedly- square bed and have the bowden length set to a value that would allow printing on the whole bed in one go -imagine a cube encompassing the whole bed- and for that you need a radius of the circumscribed circle to your bed's corby realthor - CoreXY Machines
Found a few better images online but haven't been able to track the Producer of this profile:by realthor - General
Quotethe_digital_dentist Quoterealthor Yes, I understand and agree. I was wary about the silicone springiness but couldn't think of something else especially that silicone can be high temp and is also somewhat non-slippery. In a previous iteration I did have constraints at the corners but those are not possible anymore now after I have changed several things ... I am still scratching my head forby realthor - General
Hi guys, just seen this kind of profile today at a company that imports them from somewhere. Couldn't get much info, they are 30x30, 2mm meat. Do you have any idea what variety of slot extrusion are these? Thanks.by realthor - General
It's like we are in Matrix ... looks badass. But for my SCOUTcorexy experiment I think I am going with SF-1 1012 bushings ... skipping LM10UUs altogether. I wonder if there are better variants of bushings that will keep tight tolerances and would not wear out as fast as sintered bronze bushings. But Ultimaker uses them, they must be good enough.by realthor - General
They are expensive for what I am doing. Down the road, when prices will drop 50% I will consider them. Now I am thinking of SF-1 10mm bushings instead of the massive LM10UU. Are they really worse than LM10UU from china?by realthor - General
I seen this on thingiverse yesterday and liked it... so it was an easy re-find: I agree with d_d on the extra elasticity of the flexible glue you are going tu use... it will basically introduce in the belt the very thing they are good at.by realthor - General
So I have re-designed my 8mm carriage and "ported" it to 10mm rods. It was quite tricky to keep the nozzle at the same spot (center of the YCarriage as well as at the YRods axis) and the belts' insertion points onto the XCarriage so I don't modify anything on the printer frame/etc. Finally this is what the SCOUTcorexy 10mm XCarriage looks like: The base (green) is 73mm (compared to 62mm of thby realthor - General
lol, there's no such thing ... I like better to see WIP projects than shiny stuff. Many do. We take it for inspiration. Tha't one more reason I post my WIP designs on thingiverse, specifying that they are not tested but are there so others could get some ideas or see flaws and avoid them .. nevertheless there's power in having a large pool of projects to pick whatever one needs...by realthor - General
Yeah I am trying to "port" the 8mm XCarriage previously shown here to 10mm rods/LM10UUs ... I will not go larger than that unless I'll do something and use 1515 or carbon fibre tube concotion BTW: would be interested to see your machine as I also plan to use alu tube for the frame (as well as 2020 as all parts are designed with the proper holes for 2020 extrusion)by realthor - General
Guys, what's your experience with XRods of different diameters? I have previously calculated that for 340mm of X rod (about 310 unsupported), 8mm Rods is enough for a bowden but that is static loads only, nothing dynamic. Now if you push it for speed then the dynamic loads are a magnitude greater than the static ones and 8mm could not be enough. I have started "porting" the XCarriage design to LMby realthor - General
Very strange design... why would they go with a single rod and an acrylic plate... Two rods would have been cheaper/less flimsy ... So it's the general consensus that the springs in the bed leveling bolts should be strong enough to keep the bed in position but will be too strong for an eventual crash for absorbing the shock? If that's the case why not ditch them completely like d_d did and onlyby realthor - General
I am seriously thinking of implementing some sort of renishaw_probe-style hotend, so that any head-crash would just cut the power to the motors or something like that... @dc42: ... can you post a pic or something (link?) about that? I am very curious...by realthor - General
Quoteleadinglights The Kludge* has a long and honorable tradition in engineering, sometimes working astonishingly well. The downside is that nobody pats you on the back when it works and everybody mocks you when it doesn't. Mike * Correctly the Kluge, named after a German engineer - Norbert Kluge 1860 -1887 who died at the hands of his brother Hans who stole all his best ideas. You learn someby realthor - General
Quotethe_digital_dentist A failure is a failure, whether it's a loose or broken wire, or malfunctioning code. I don't know every possible reason (stray beta particles from radioactive decay in the uCs plastic packaging?), but controller boards occasionally behave contrary to their programming. Noise on the power or logic inputs can cause all sorts of odd behavior, and with a minimum of 4 motorsby realthor - General
Guys, I don't get it... linear bearings (LM8UU/etc) have some play in them due to tolerances, maybe to poor construction, etc. Whether they are encased in SC housings or the longer LM[...]LUUs are used, the play is there anyway. One could use pillow block bearings or adjustable preloading bearings but both solutions are costly (costlier then LM[...]UUs anyway). It has been suggested that printedby realthor - General
Quotethe_digital_dentist You can put in all the switches you want, but if the electronics fails to recognize the switches, bad things may happen. The only way to really protect the extruder from a head crash is to mechanically prevent the bed from moving high enough to hit the nozzle or prevent the nozzle moving low enough to hit the bed. The same is true for the extruder and bed heaters. Youby realthor - General