jitsbuild-yaxis
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jitsbuild-yaxis [2012/11/09 23:34] jit |
jitsbuild-yaxis [2012/11/17 02:23] (current) jit |
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| - | **jit's build: Y axis** | + | ===jit's build: Y axis=== |
| (Go back up to [[jitsbuild|jit's build]]) | (Go back up to [[jitsbuild|jit's build]]) | ||
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| The three metal parts on the left will be shorter if you have a model smaller than 8". | The three metal parts on the left will be shorter if you have a model smaller than 8". | ||
| - | Start with the Y front end (the printed part without the motor). Loosen the two M5 screws until the nuts are flush with the ends of the screws, and then loosen them a bit more (but not enough so that the screws fall out of the nuts). Insert the aluminum extrusion the only place it can go (check image below for which end to use) and slide it all the way in. You may have to adjust the height of the nuts to clear the edges of the channel. When the extrusion is fully inserted, tighten the screws. | + | Start with the Y front end (the printed part without the motor). Loosen the two M5 screws until the nuts are flush with the ends of the screws, and then loosen them a bit more (but not enough so that the screws fall out of the nuts). If the nuts fit tightly into their niches, you may have to force them outwards by pushing on the screw heads. Insert the aluminum extrusion the only place it can go (check image below for which end to use) and slide it all the way in. |
| - | Do the same thing with the Y back end. Be careful that you don't damage the endstop or its wires, if you have already installed it. | + | If it doesn't want to go in, trim the plastic. Use a file or a sharp woodworking chisel to remove enough at the end so that you can get the extrusion started. Once the plastic part is inserted a little into the extrusion, you may be able to use the extrusion itself to remove the excess plastic. You might be able to get the part the rest of the way in by hand, or you may need to use a rubber or plastic mallet; use one hand to keep the parts lined up, and tap gently: |
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| + | {{wiki:jitsbuild:mallet.png}} | ||
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| + | (This image actually shows a different set of parts, and the screws and nuts are missing, but the principle is the same. The image below is also from a different part of the printer.) | ||
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| + | You may have to adjust the height of the nuts to clear the edges of the channel. | ||
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| + | {{wiki:jitsbuild:nut-alignment.png}} | ||
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| + | Tap the piece in a little at a time, so that you don't accidentally tap on it when a nut is caught against the end of the extrusion. Make sure there is never any gap between the bottom face of the extrusion (the face with two slots) and the plastic part; it must be flush. | ||
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| + | When the extrusion is fully inserted, tighten the screws. | ||
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| + | Next, prepare the hardware that will attach the Y axis to the frame bottom. Get two M5x8mm button-head screws and screw one nut on each, just until the nut is flush with the end of the screw. Slide the head of one screw into one of the channels on the bottom of the extrusion, and then slide the head of the other screw into the other channel. Move them toward the middle, then insert the Y back end into the extrusion. | ||
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| + | Fully seat the Y back end, just as you did with the front end. Tighten the screws. | ||
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| + | While installing the Y back end, be careful that you don't damage the endstop or its wires, if you have already installed it. | ||
| Bottom view: | Bottom view: | ||
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| {{wiki:jitsbuild:y-tensioner3.png}} | {{wiki:jitsbuild:y-tensioner3.png}} | ||
| - | At this point, pick up the carriage by one rail and let the carriage, and the big loop of cable, dangle. The big loop should be flat. If it is pretzel shaped, or saddle-shaped, then it is twisted. Pull the cable back out of the part on the right and take the twist out, then re-insert it. The cable should be dangling in a plane. | + | At this point, pick up the carriage by one rail and let the carriage, and the big loop of cable, dangle. The big loop should be flat. If it hangs in a shape like a figure-8 or a saddle or a pretzel or worse, then it is twisted. Pull the cable back out of the part on the right and take the twist out, then re-insert it. The cable should be dangling in a plane. |
| Insert the free end through the last tensioner hole, leaving a loop big enough to grab: | Insert the free end through the last tensioner hole, leaving a loop big enough to grab: | ||
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| Next, check the portion of cable between the Y front end pulley (the one without the motor) and its nearest tensioner. If it needs adjustment, you have to remove the M8 bolt and nut and bearing/pulley and adjust the number of washers. You need at least one washer there, but you can add more. On this build, two were needed to get the cable flat. (Make sure you relieve the tension in the cable before you start to loosen that bolt!) | Next, check the portion of cable between the Y front end pulley (the one without the motor) and its nearest tensioner. If it needs adjustment, you have to remove the M8 bolt and nut and bearing/pulley and adjust the number of washers. You need at least one washer there, but you can add more. On this build, two were needed to get the cable flat. (Make sure you relieve the tension in the cable before you start to loosen that bolt!) | ||
| - | After checking the cable alignment in that plane, you need to go back and check the alignment in the first plane again. Every time you adjust one of these things, you have to go back and check all the others. This is because the procedure described here uses visual cues such as the edges of things or that groove, which means you are looking along a direction which is almost but not exactly parallel with one of the axes; therefore, each adjustment be not quite orthogonal with any of the axes, and will affect two measurements. | + | After checking the cable alignment in that plane, you need to go back and check the alignment in the first plane again. Every time you adjust in one plane, you have to go back and check the other plane. This is because the procedure described here uses visual cues such as the edges of parts, or that groove, which means you are looking along a direction which is almost but not exactly parallel with one of the axes; therefore, each measurement will be not quite orthogonal with any of the axes, and will be affected by both adjustments. |
| So go back and forth between the planes, iteratively, until everything is close enough. After each step, make sure the cable is tight, as tight as you can get it by pulling on the small loop with your hand. | So go back and forth between the planes, iteratively, until everything is close enough. After each step, make sure the cable is tight, as tight as you can get it by pulling on the small loop with your hand. | ||
| - | Now take a careful look at the entire Y axis. Double-check everything: how the bearings fit into their holders, how the cable fits, and so on. When you are satisfied, take the slack out of the smaller loop. Grab the loose end of the cable and pull. It will take a bit of force to get the cable completely into the slot on the tensioner: | + | Now take a careful look at the entire Y axis. Double-check everything: how the bearings fit into their holders, how the cable fits, and so on. Slide the carriage back and forth and check the angles of the cables. When you are satisfied, take the slack out of the smaller loop. Grab the loose end of the cable and pull. It will take a bit of force to get the cable completely into the slot on the tensioner: |
| {{wiki:jitsbuild:y-tensioner9.png}} | {{wiki:jitsbuild:y-tensioner9.png}} | ||
| - | There is a lot of cable hanging out of this assembly. Don't cut all that off. If you ever need to completely disassemble this, you will need some of that slack to get it back together again. For now, wrap the cable around the carriage: | + | There is a lot of cable hanging out of this assembly. Don't cut all that off. If you ever need to completely disassemble this, you will need some of that slack to get it back together again. And if you ever decide to switch to longer metal parts to get a larger build volume, you can re-use the same cable if you haven't cut it. For now, wrap the cable around the carriage: |
| {{wiki:jitsbuild:y-tensioner10.png}} | {{wiki:jitsbuild:y-tensioner10.png}} | ||
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| Secure the wires so nothing will snag on them while you work with the Y axis, and set it aside. | Secure the wires so nothing will snag on them while you work with the Y axis, and set it aside. | ||
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jitsbuild-yaxis.txt · Last modified: 2012/11/17 02:23 by jit
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