projects:welcome
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projects:welcome [2017/11/14 18:35] jerzydziewierz |
projects:welcome [2017/11/14 19:30] jerzydziewierz |
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| It is likely approx. 40 years old. There is no driver electronics whatsoever, but there is: | It is likely approx. 40 years old. There is no driver electronics whatsoever, but there is: | ||
| * high precision rails on both axes. No play. No rust, no damage. | * high precision rails on both axes. No play. No rust, no damage. | ||
| - | * Linear motors. There are noiseless. Known coil resistance: 14 ohms. Tested working. | + | * Linear motors. There are noiseless. Known coil resistance: 14 ohms. Tested working |
| * Ultra high precision linear encoders, with sine-cosine output. Tested works at 5V supply. | * Ultra high precision linear encoders, with sine-cosine output. Tested works at 5V supply. | ||
| - | * elastic covers to all axes. | + | * elastic covers to all axes. This makes it a very pro-looking machine. |
| We need to build the servo amplifier and the motion controller for it. | We need to build the servo amplifier and the motion controller for it. | ||
| Line 31: | Line 31: | ||
| At this point, there would be no noise, no dust, no vibration e.t.c. | At this point, there would be no noise, no dust, no vibration e.t.c. | ||
| This is because: | This is because: | ||
| - | * the machine is not actually operable. The servo amplifiers are missing and there is no end effector on it. | + | * the machine is not actually operable. The servo amplifiers are missing and there is no end effector on it. |
| - | * When powered, the movement of the primary axes is completely noiseless. This is because these are linear servo motors optimised for ultrasonic research and hence optimised for not generating acoustic noise (which would interfere with measurements). These kind of motors are very unlike stepper motors (which would buzz). | + | |
| - | * When we are ready to install the end effector, this will be the point to consider the amplitude of noise and dust generation: | + | |
| - | ** for a 3D printer head, we can all agree that regular ventilation & noise would make it acceptable | + | * When powered, the movement of the primary axes is completely noiseless. This is because these are linear servo motors optimised for ultrasonic research and hence optimised for not generating acoustic |
| - | ** for a precision 3D scanner head (actually, one of the original uses of this machine) there would be no noise whatsoever | + | * When we are ready to install |
| - | ** for a general purpose CNC machine: I am afraid that this table is not really suitable for a general-purpose CNC operation. This is because the linear motors will have a very limited force that they can exert. Hence, I believe | + | * for a 3D printer head, we can all agree that regular ventilation & noise would make it acceptable |
| - | ** for a PCB router: This is much more possible to do. It is possible to build a low power dust extractor from base materials | + | * for a precision 3D scanner head (actually, one of the original uses of this machine) there would be no noise whatsoever |
| - | ** a spark erosion processor: In such case, there is no dust, no noise, and the end product could be of extremely high quality (injection moulds are often finished with this technique). This method is limited by the available electric power, and in general, very slow. EM interference can be managed by enclosing the working area in a Faraday cage. | + | * for a general purpose CNC machine: I am afraid that this table is not really suitable for a general-purpose CNC operation. This is because the linear motors will have a very limited force that they can exert. Hence, I believe that with current motors, metal and wood processing would not be feasible. One could think about installing stronger motors, but really, that would cost a lot. In any case, if we decide to do this, the dust would have to be extracted up to a cleanroom standard (possible, but not cheap) and the noise would be a serious consideration. High-quality spindles (with controlled runout) actually do not create that much noise, but they cost cost cost. |
| + | |||
| + | * for a PCB router: This is much more possible to do. It is possible to build a low power dust extractor from base materials ( i actually have all the parts that I can contribute). The noise would be manageable. | ||
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| + | * a spark erosion processor: In such case, there is no dust, no noise, and the end product could be of extremely high quality (injection moulds are often finished with this technique). This method is limited by the available electric power, and in general, very slow. EM interference can be managed by enclosing the working area in a Faraday cage. | ||
| ----------- Risk: Health and Safety from the moving parts ------------ | ----------- Risk: Health and Safety from the moving parts ------------ | ||
| [2017-11-14] | [2017-11-14] | ||
| + | |||
| [Bob]: H&S? | [Bob]: H&S? | ||
| Line 55: | Line 58: | ||
| To mitigate this risk, we could: | To mitigate this risk, we could: | ||
| - | (proposal 1): Build it into a lockable cabinet to make it even more obvious that it is not to be messed with. | + | |
| - | (proposal 2): Instead of a cabinet, we could install a nightlatch on each of the two heavy axes: https:// | + | * (proposal 1): Build it into a lockable cabinet to make it even more obvious that it is not to be messed with. |
| + | | ||
| --------- Risk: How to remove it from the club after the interest wanes out ------------ | --------- Risk: How to remove it from the club after the interest wanes out ------------ | ||
| - | [2017-11-14] | + | [2017-11-14] |
| [Bob]: In case if the interest stalls, it will be difficult to get rid of it. | [Bob]: In case if the interest stalls, it will be difficult to get rid of it. | ||
| Line 65: | Line 69: | ||
| [Jurek]: I must agree with this. | [Jurek]: I must agree with this. | ||
| In order to mitigate this risk, | In order to mitigate this risk, | ||
| - | (proposal 1): I suggest that we start a fund, to be held by the CCA, in which there will be a deposit to cover the machine’s eventual disposal. I guess we might need to find somewhere in range of 300gbp . | + | * (proposal 1): I suggest that we start a fund, to be held by the CCA, in which there will be a deposit to cover the machine’s eventual disposal. I guess we might need to find somewhere in range of 300gbp . |
| - | (proposal 2): Another method might be to get an official quote from one of the scrap metal collectors: | + | |
| https:// | https:// | ||
| since there is easily 300kg of metal in this thing, I would guess they might be interested in picking this thing up for free from us. | since there is easily 300kg of metal in this thing, I would guess they might be interested in picking this thing up for free from us. | ||
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projects/welcome.txt · Last modified: 2018/05/28 17:25 by emil.carr
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