Z axis Problem
时间：2012-08-09 17:02 来源：未知 作者：admin 阅读：次
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all, Just upgraded my makerbot after half a year of inactivity, my z-axis isn't quite working proper now. I've greased the rod and tried tensioning and loosening the belt, but it just keeps stuttering. It seems to be smooth much more often over certain heights though. Here's a clip of the issue. http://www.youtube.com/watch?v=8aujfiU4kBI Looking forward to your help! Thanks! Just upgraded my batch12 cupcake to a mk6+ with smd v3.3 Motherboard v2.4 Gen3 smd v2.3 for X, Y, Z axis Jetguy 30 Aug 2011, 21:50 GMT+0800Cupcakes are known for having rod binding issues. Did you upgrade to the new high torque nema 17? If not, I highly recomend you do that for all three axis with the new gen4 electronics. http://store.makerbot.com/nema-17-stepper-motor-330.html Also, did you calibrate your stepper currents? On a cupcake you may have to adjust the Z current higher than what is listed in the table and use the old values from the X and Y motors. If you didn't upgrade your motors then you will be running higher than 0.6V REF. Leave the other values the same and only change the REF. I'm thinking somewhere in between 0.6V and 0.8 Volts. The motor is rated at 0.4 Amps, and the driver registers 2 volts for 1 amp of current, thus 0.8 is the "proper" setting because it's basically double the volts to reach the smpas required. The new motors require a much higher REF voltage because they are rated at 0.8 amps or double the power of the original Cupcake motor. You can try editing the thingomatic.xml to lower the feedrate for z to 100 or lower stock cupcake defintion below: <axis id="z" length="100" maxfeedrate="100" stepspermm="1280" endstops="min"/>Now, here is the big question, what driver are you using in rep-g? You can honestly get away with using a standard thingomatic with ABP or HBP driver in rep-g but you have to "fix" the z axis steps per mm. From the above copy from the cucpake original XML, the 8mm threaded rod has a pitch of 1.25 and we were driving it with single step drivers (200 steps equals 1 rotation). The T-O-M uses a 4 different screw that requires a totally different steps per mm, 200 to be exact. If you set the z axis driver board to 1/8th step, that means we need to send it 4 times as many steps to go the same distance. So to recap, we have 2 factors, different drivers and different screws. If you are using the driver set to 1/8th step and stock cucpake screws, we have to send 1280 steps because the stock cupcake took 320 steps to go 1mm. Your z axis defintion in the driver youa re using needs to be this: <axis id="z" length="116.3" maxfeedrate="240" stepspermm="1280" endstops="max"/>Also, while on the subject of edits. the length listed in each axis should match the actual travel length of your bot. That setting adjusts the size of the base grid and the box above it to show you the actual build area of your machine, so you can see before you print something if it will fit on the build platform or max out the height of your bot. All that being said, you now have to use a skeinforge 35 profile for Thingomatic ABP/HBP and stepstruder MK6, but you must use a start and end .gcode files from an SF 006 profile for cupcake that doesn't inlcude homing if you didn't install the endstops. If you did install enstops and they work, you can use a thingomatic profile, with only slightly edited start and end.gcode and the only thing you need to modify is the waiting position. stock it's going to be : G1 X57 Y-60.0 Z10 F3300.0 (move to waiting position)but you need something more like G1 X51 Y-51.0 Z10 F3300.0 (move to waiting position)The end .gcode would hit the ends of the bot for sure and since we don't get max endstops, it's bad if you forget this edit too. G1 X0.0 Y51.0 F3300.0 (move to cooling position)I also like to put a command to move the z up to max before we did the x and y motions (as long as we have a working endstop) to ensure we clear the part. G1 Z150 F100.0 (move to cooling position Z max) Last edited on 30 Aug 2011, 22:56 GMT+0800 by Jetguy + Show more Also, I'm posting that info so others can understand how to edit the start and end gcode. If you understand that file, you can do all kinds of tricks. You can edit the end code to play music everytime the print is done. You can clean nozzles on a remote wipe tab. It's much better to know what is going on in that file than for me to just hand them out. antibin 31 Aug 2011, 00:46 GMT+0800 Hey thanks for the swift response Jetguy! I've calibrated the stepper current according to the table. Don't have the new motors and end stops though, I'll leave it for another time, shipping to Singapore is really costly and time-consuming. the only thing i have is a spare Keling nema 23 motor.. I'm using the thingomatic ABP MK6 driver. Tried the edits, there were beeps and sounds but didn't seem to move the motor. Have been playing around with the values, but one thing looks consistent, the motor seems to be under stress when the platform's at certain height of the threaded rod. I think I might have some issues with the rods, gonna cut a new set first thing tomorrow and have another go. Thanks for pointing to the edits, wouldn't have known where to look for these settings! [size=1.2em]Re: Z axis Problem Hello again, I've replaced my threaded rods and it's much better now though there're still quite some wobbling. Moving on, I've adjusted the stepspermm for my Thing-o-matic with ABP and MK6 driver to calibrate the distance moved with the values in the control panel. So I got the platform centere and used the skeinforge 35 profile for my prints. But before it prints, it tries to move the platform beyond where it can go when it homes to XY minimum, clashing with the z axis rod on the front left. How do I calibrate it properly without endstops installed? I tried adjust the lengths for XY axes on thingomatic.xml, just doesn't seem to work. Last edited on 2 Sep 2011, 01:35 GMT+0800 by antibin + Show more Jetguy 2 Sep 2011, 04:05 GMT+0800 As I've stated, the values in the machine.xml only change the platform view in replicator-G and have nothing to do with a physical limit. Your problem is the start.gcode which I told you to edit and use one from a Cupcake SF 0006 folder and copy that to your SF 35 profile folder. CNDdrdave 5 Sep 2011, 02:20 GMT+0800 On My CUPTHING - Z mods I did - Smaller Pulley (Try 1st cheep) + then if still not right - Acme Rods ($100) from ebay (folks in FLA) If you use the smaller drive pulley with stock rods, you will have better results than with the big Z pulley. (Chg in machine.XML "change the scale factor in the ReplicatorG ‘machines.xml’ file to accomodate the new change in movement between the new pitch of the rods and the new smaller pulley. On ours the default was 320, and I think we ended up around 338." - (With Acme Rod Mod 331 calibrated) w/o Acme - using smaller Z pulley - On Makerbot site its called "XY Motor Pulley " $14.15 SHIPPED- Same value as X and Y = stepspermm="11.767463 A Step up from that would be to use the Acme Z rods (ebay) AND the smaller pulley <axis id="z" length="131" maxfeedrate="213" stepspermm="331" endstops="min"/> This fixed ALL Z Issues completely for me. In retrospect, the smaller pulley MIGHT be enough to solve issues with stock rods as far as repeatability (for wobble issues - you need the acme rods really to make it perfect) |
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