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Discuss here what makes your printer moving.
Heatbed mosfet @30A, 12V - 8 years ago
Hey, I have gotten my self a silicon-heating-pad that runs 12V, 360W ( 30A) . This is fixed, it could be argued that it would have been better to get a AC heating pad, or 24V pad..... But here we are. Also buying a ready made module is not an option. I have come across two potential components that I think can run it, now I just want to make sure that I am not making anything stupid so I ask heby LarsK - Controllers
Re: Rugged CoreXY - 8 years ago
On that printer the idlers on the Y axis are cantilevered. That is, they are not supported from both top an bottom. You see the screw comes through what looks like a 5mm plate and that and the clamping should hold the idlers in place. I have come to believe that The Digital Dentist is right in his proposal where he supports all the idlers both top and bottom. It does make installation a bit moreby LarsK - CoreXY Machines
Re: Corexy issues advice needed - 8 years ago
Just for clarification, it is not play we are looking for. Play means when the idlers can move because a hole is too big or something like that. What I was looking for, was if the belt under load forces the idlers to bend in a direction. Maybe that is what you did, but just to clarify in case. Nobody seemed to want to post a belt video, so here is one I shot from the printer I am currently workby LarsK - CoreXY Machines
Re: Corexy issues advice needed - 8 years ago
I agree with The Digital Dentist that your belts are flexing - But I don't think it is belt tension. I think it is the idler posts. When the printer changes direction the load on the idlers (marked with read below) changes and the idler posts flexes slightly. If this is true it should be visible if you feel with your finger on the screw that secures the idler while it is running To fix thiby LarsK - CoreXY Machines
Re: Corexy issues advice needed - 8 years ago
It seems when the printer is making the same movement all the time it returns to the same position. I still say either the hotend can move or the idlers are flexing. For further diagnostic I think you will need to make a video of it running while printing something difficult. The video should show all the idlers where the belts passes and the hotend itself.by LarsK - CoreXY Machines
Re: Corexy issues advice needed - 8 years ago
I still think you should try to print a different geometry and show us that also (or just show the cube). It is important if the error is geometry dependent or not.by LarsK - CoreXY Machines
Re: Corexy issues advice needed - 8 years ago
Can you show a photo of the cube you said printed OK? If the quality is dependent of the many changes in direction which are done for the gear, then that, for me, is an indication that it is not bed but the CoreXY system. For me two things comes to mind when looking at the photo of your printer; 1) The post holding your belts are tall. Maybe the idlers can flex slightly inwards when loaded.by LarsK - CoreXY Machines
Re: Rugged CoreXY - 8 years ago
Quotelkcl hiya larsk, sorry i am extremely busy, i'm no longer able to focus full-time like i have been for the past 3 months, so apologies i didn't have time to go back and find who it was, or exactly what was said - sorry about that. brief comment: relying on the centre fibre does not strike me as sensible, at all. the belt's specifications are almost certainly quoted for an evenly-distributeby LarsK - CoreXY Machines
Re: Voron 3D printer uses just one bearing per XRod... is that a smart choice? - 8 years ago
* The distance from the center of rotation to the nozzle, as you your self made such a nice sketch about recently. * Tooth side of belt running on smooth idlers * 4 point bed leveling on a alu slab * Bed with 2x Z-screw and those screws seems supported in a way much like the Prusa, which I don't agree with. In the current design with so many rods it is probably OK. * Bed rods held by printeby LarsK - CoreXY Machines
Re: Rugged CoreXY - 8 years ago
Quotecozmicray Looks like Flat / Vee belt section of the handbook Does it have a timing / Power Transmission belt section HANDBOOK OF TIMING BELTS AND PULLEYS. Not good enough? You can twist a timing belt all you want but The common ones we use --- are NOT designed to be twisted best to design for what the belt was made to do Page 199 give you the tolerances for angular misalignment. Itby LarsK - CoreXY Machines
Re: Rugged CoreXY - 8 years ago
Quotehobbymods I wont be twisting belts or having them run hard against flanges. I will extend the shaft on each stepper so that the drive pulley will be on the correct plane for each of the 2 circuits, and do some sort of pedestal bearing mount to support that extension. I've got toothed idlers coming for where it turns on the toothed side and plain idlers for the other, I'm not going to all tby LarsK - CoreXY Machines
Re: Rugged CoreXY - 8 years ago
Quotelkcl but as the carriage approaches an idler that's angled, those tension variations are *going to change* dependent on the length. . This quoted part is not accurate. There are no change in length. The 90 deg rule for belts that changes length is universal. About strain in the belt; As long as you are in spec for the belt you can twist and turn it as you like. What matters is thatby LarsK - CoreXY Machines
Re: Rugged CoreXY - 8 years ago
I am not sure I understand how you just went and entirely disregarded the force exerted by the plastic through the bowden tube? Lets say you put a stepper with 0.4Nm as extruder. Then you have a 10mm hubbed bolt. That is a radius of 5mm. This gives a forward force of 80 N (!) on the plastic. Even if only half of the 0.4Nm is exerted or makes it through the bowden, then that is still 40 N or ~4kgby LarsK - CoreXY Machines
Re: Would a hybrid Horizontal-Vertical XCarriage bring any advantage? - 8 years ago
Just like we hold most other things. Imagine this with a hole equal to the outer diameter of the hotend> It can be anything. You just want to support it firmly so it dosent go side to side. Also - On the same subject, in my opinion, you should enclose the hotend so you do not have any cooling air escaping down on the part being printed, but there is no consensus about the strict necessiby LarsK - CoreXY Machines
Re: Would a hybrid Horizontal-Vertical XCarriage bring any advantage? - 8 years ago
Quick comments: Basically, for any design with two smooth rods you pay a toll on the print area. The distance from rod to rod plus bearing size is print area lost relative to your outer frame diameter. A bigger outer frame means more bracing and more weight all around. The decision about mounting the two rods vertically or horizontal is then in-parts about either sacrificing Z height (verticaby LarsK - CoreXY Machines
Re: Rugged CoreXY - 8 years ago
I set the resulting moment arrow wrong. Please excuse my poor skills in FBD.by LarsK - CoreXY Machines
Re: Rugged CoreXY - 8 years ago
As a general comment to the above - We return to the predicament that nobody really knows the load at the hotend. The belts/pulley system we can at least approximate with the stepper motors torque values and assuming a pre-loading on the belts. But what are the forces exerted through the hot-end drag on the plastic and what is the force (and thus induced turning moment) from the bowden intoby LarsK - CoreXY Machines
Re: Is this an insane way to mount extruders? - 8 years ago
Quotedeckingman I'm a bit concerned about what happens to the tubes when the hot end is directly under the extruders. They'll need buckle and bend a lot when the distance to the hot end reduces by 150mm to 200mm. That might induce some twisting forces to the carriage, although it's riding on 2 linear guides and should be well constrained. It's still a bit of a concern though. Now if only the extby LarsK - CoreXY Machines
Re: Is this an insane way to mount extruders? - 8 years ago
It is an interesting idea but your build area is not that big. I think an outer frame of 600 x 600 for 320 x 340 build sounds big but lets go with those numbers, lets also assume that the bed is in center of that. You now mount it on the length side with 340. Lets call that length Y That gives you a maximum distance from extruder to hotend of: X: 600/2 + 320/2 = 460 mm Y: 340/2 = 170by LarsK - CoreXY Machines
Re: Rugged CoreXY - 8 years ago
@ Ikcl - I like your focus on reducing the length from center of X rods to edge of out nozzle. I have never understood that it was not given more attention. Mine is 33mm from center of rods to nozzle edge, I wish it was less, but it is hard to design something printable and something that won't melt and then I wanted the dual nozzles... But sometimes I see some designs that makes me confused...by LarsK - CoreXY Machines
Re: Rugged CoreXY - 8 years ago
Quotecozmicray I got a headache reading all the stuff on stacked belt bearings a drawing of two level system Let you guys rip it apart ???? Nice drawings. Just, it is not that simple. The design you just sketched offset one of the idlers on the y carriages into the print area. Since this happen on both sides you loose 2x bearing size as potential print area. Using 16 mm idlers and yoby LarsK - CoreXY Machines
Re: Rugged CoreXY - 8 years ago
QuoteJamesK QuoteLarsK Also, the distance between the two attachment points can be minimized to within 2mm (I say min 2 mm between running belts), no rules says the belts has to be far apart. The attachment points on the X carriage? As far as I can see, there's no relative motion between the belts once they enter the X axis. You can clamp the belts together on the X carriage if you want. It woulby LarsK - CoreXY Machines
Re: Rugged CoreXY - 8 years ago
Quotehobbymods And THAT'S why he's got the X axis plate down in the hole level with the main plate, losing all that X travel, but i'm getting the same effect by running my pulleys on raised pedestals And looking at this pic (and assuming it's done correctly) he does have the belts connected to the central carriage at different heights. Mind you he also has pieces of bronze bush epoxied to thingsby LarsK - CoreXY Machines
Re: Rugged CoreXY - 8 years ago
Quotelkcl Quotehobbymods I do get it about the twisting force in the carriage, and while the linears I'm using would probably handle it it certainly wouldn't be ideal. very very busy, partly answering dd's question as well: ... unless the belts are offset in height (stacked one above the other - different use of word "stacked") you can NOT do the above trick which eliminates twisting force undeby LarsK - CoreXY Machines
Re: My new CoreXY completed build- Issues - 8 years ago
Did you ever solve this? I am looking at something similar. Personally I am attributing it to the nozzle not being properly fixated so that it will be ever so slightly tilted by being dragged over plastic. How lose is your hotend when you try to push it side to side touching the nozzle?by LarsK - CoreXY Machines
Re: Just an observation: by the number of "new topics", CoreXY doesn't seem to be all that popular :-/ - 8 years ago
Maybe the CoreXY attracts people who are pretty handy at figuring the basics out them self? So we don't see many "what kind of motor" topics here. I have been off these forums for a time and it is in part because I feel we are maybe circling a little too much around the same experiences we each have. This hobby takes time - lots of time - and it really takes time to support a short post with reby LarsK - CoreXY Machines
Re: Coffeetable CoreXY:: new build :: small apartment rep-strap solutions - 8 years ago
Oh, in the above calibration link. Getting within 0.05 on all the dimensions as one guys does - That is not normal I think. Only an absolute fraction of a fraction of hobby printers can do that.by LarsK - CoreXY Machines
Re: Coffeetable CoreXY:: new build :: small apartment rep-strap solutions - 8 years ago
Modular versus uni-body. Easy configurable and up-gradable versus tailored for the exact purpose. It is an interesting balance. I went heavy towards modular and upgradable on my first self-designed printer. Lots of parts, many "off the shelf" metal components. The printed parts were small and simple. Prior experience with my delta what I have had to take my effector apart so many times made mby LarsK - CoreXY Machines
Re: Coffeetable CoreXY:: new build :: small apartment rep-strap solutions - 8 years ago
QuoteDon't design parts that do multiple functions because if something breaks you'll have to re-print the whole part; I will say my experience is the opposite, I try to design as complex pieces as possible because every time you have an interface you have an imperfect surface meeting another imperfect and bolts that applies localised stress and variations in the print dimensions. That was myby LarsK - CoreXY Machines
Re: Coffeetable CoreXY:: new build :: small apartment rep-strap solutions - 8 years ago
Having to start partly or completely over on a design happens to everybody. I still have my multicolor hotend sitting on a shelf staring at me ( ). Good luck with the new design. I don't know where you are with your Delta, but if it can print then try to print the parts you already designed even if you don't intend to use them. It is a great experience to see your parts alive and get a feel foby LarsK - CoreXY Machines