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projects:welcome [2017/11/14 20:45]
jerzydziewierz
projects:welcome [2017/11/27 20:58]
jerzydziewierz readability
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 The machine itself is very robust. ​ The machine itself is very robust. ​
  
-It is likely approx. 40 years old, but for what it is, it has seen only a very light use. It was used to guide an ultrasonic probe in a water tank. The baseand the bridge is solid steel; it is very rigid. It weights no less than 300kg.+It is likely approx. 40 years old, but for what it is, it has seen only a very light use. It was used to guide an ultrasonic probe in a water tank. The base and the bridge is solid steel; it is very rigid. It weights no less than 300kg.
  
 There are no driver electronics whatsoever, but there is: There are no driver electronics whatsoever, but there is:
  
-  * high precision rails on both axes. No play. No rust, no damage. Noiseless.+  * High precision rails on both axes. No play. No rust, no damage. Noiseless.
   * Linear motors. These are noiseless. Known coil resistance: 14 ohms. Tested working with 2A current, although, we'd have to test how much can they take before overheating. Ideally, they need onboard temperature monitor.   * Linear motors. These are noiseless. Known coil resistance: 14 ohms. Tested working with 2A current, although, we'd have to test how much can they take before overheating. Ideally, they need onboard temperature monitor.
   * Ultra high precision linear encoders, with a sine-cosine output. Tested works OK at 5V supply.   * Ultra high precision linear encoders, with a sine-cosine output. Tested works OK at 5V supply.
-  * elastic covers ​on both axes. This makes it a very pro-looking machine. ​+  * Elastic scarf on both axes. This makes it a very pro-looking machine ​and makes it hard wearing
  
 +I believe it can still serve the good of humanity for many years to come.
  
 == What is missing: == == What is missing: ==
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   * We need to build the servo amplifier and the motion controller for it. Budgetary cost ~~200gbp   * We need to build the servo amplifier and the motion controller for it. Budgetary cost ~~200gbp
   * We need to build a motion controller for it. *machinekit* has been suggested. As far as I understand, the club has a beaglebone black waiting for such opportunity. ​   * We need to build a motion controller for it. *machinekit* has been suggested. As far as I understand, the club has a beaglebone black waiting for such opportunity. ​
-  * We need to supply an end effector - e.g. 3D printer head or other.+  * We need to supply an end effector - e.g. 3D printer heador other.
  
  
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 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. 
  
- ​* ​When powered, the movement of the primary axes is completely noiselessThis 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)+ ​* ​The machine ​is not at this point operableThe servo amplifiers ​are missing ​and there is no end effector on it.
  
- * When we are ready to install the end effectorthis will be the point to consider the amplitude ​of noise and dust generation:+ * When powered, the movement ​of the primary axes is mostly noiseless. This is because these are linear servo motors optimised for ultrasonic research ​and hence optimized for not generating acoustic noise (which would interfere with measurements). These kind of motors are very *unlike* stepper motors (which would buzz). ​
  
- * for a 3D printer head, we can all agree that regular ventilation & noise would be acceptable. Possiblykeep the window open to prevent accumulation of fumes. Otherwise, ​the risks are low.+When we are ready to install the end effectorthis will be the point to consider ​the amplitude of noise and dust generation:
  
- ​* ​for precision ​3D scanner ​head (actuallyone of the original uses of this machine) there would be no noise whatsoeverBudgetary cost ~150gbp+ ​* ​For a 3D printer ​head, we can all agree that regular ventilation & noise would be acceptable. Possibly, keep the window open to prevent accumulation of fumes. Otherwise, the risks are low.
  
- ​* ​for 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 rather 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 considerationHigh-quality spindles (with controlled runout) actually do not create that much noise, but they cost cost cost. + ​* ​For precision 3D scanner head (actually, one of the original uses of this machine) there would be no noise whatsoeverBudgetary ​cost ~150gbp
  
- ​* ​for PCB routerThis is much more possible to doIt is possible to build a low power dust extractor from base materials ( i actually have all the parts that can contribute)The noise would be manageableWe would need to buy in or make high-quality ​spindle; budgetary ​cost is ~200-500gbp.+ ​* ​For general purpose CNC machineI am afraid that this table is not really suitable for a general-purpose CNC operationThis is because ​the linear motors will have a rather limited force that they can exertHence, I believe that with current motors, metal and wood processing ​would not be feasibleOne 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. 
  
- * 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. Budgetary cost: Unknown, but no less than 500gbp.+ ​* ​For 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. We would need to buy in or make a high-quality spindle; budgetary cost is ~200-500gbp. 
 + 
 + * A spark erosion processor ​(EDM): 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 in general, very slow, but on the up side, it is noiseless and easy on the enviroment. EM interference can be managed by enclosing the working area in a Faraday cage. Budgetary cost: Unknown, but no less than 500gbp.
  
  
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 [Bob]: H&S? [Bob]: H&S?
  
-[Jurek]: I to have to give You that this machine could potentially be an H&S issue. It has heavy moving parts. There is no sharps, but there is a potential for finger capture if one puts his finger into just the right place at just the right time.+[Jurek]: I do have to give You that this machine could potentially be an H&S issue. It has heavy moving parts. There is no sharps, but there is a potential for finger capture if one puts his finger into just the right place at just the right time.
    
-The risks are mostly similar to the ones coming from a regular 3D printer (that is already ​thereor the motorized table saw, which is also already there.+The risks are mostly similar to the ones coming from a regular 3D printer (that we already ​have in the cluband less than the motorized table saw that is also already there.
    
 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 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://​www.ironmongerydirect.co.uk/​product/​yale-77-traditional-nightlatch-nickel-bronze-603896 ​ ; there is enough space there to install it, and it would prevent people from moving the axes by hand (and trapping their fingers in the process). ​   * (proposal 2): Instead of a cabinet, we could install a nightlatch on each of the two heavy axes: https://​www.ironmongerydirect.co.uk/​product/​yale-77-traditional-nightlatch-nickel-bronze-603896 ​ ; there is enough space there to install it, and it would prevent people from moving the axes by hand (and trapping their fingers in the process). ​
 +
 +Since it is ours, it is OK to drill and tap holes. We can modify it any way we want.
 +
  
 == 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  ==
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 [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:   * (proposal 2): Another method might be to get an official quote from one of the scrap metal collectors:
 https://​www.yell.com/​s/​metal+collection-glasgow.html https://​www.yell.com/​s/​metal+collection-glasgow.html
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 +---------------------------
  
 ====== Wooden CNC Machine ====== ====== Wooden CNC Machine ======
projects/welcome.txt · Last modified: 2018/05/28 19:25 by emil.carr