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#1
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Waterjet Project - Puerto Ordaz Venezuela
Hi MechMate forum.
My project is building a 8 x 4 waterjet cutter machine under the mechmate configuration (OM motors, gecko drivers, V rails, pmdx bob etc). I have read a good part of the forum and i must say that have been very useful. Congratulations to the leaders and the whole community. |
#2
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motors for a waterjet
Hi. for mi project of building a mechmate configuration waterjet cutter y decide for the PK296A2A-SGXX motors. If the waterjet cutting speed ranges from 4 to 30 ipm. ¿would it be adecuate to choose a 18.1 or 36.1 geared motor to avoid the motor resonance at low RPMs .
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#3
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I don't think resonance will be problem with modern drives, and you also need speed for rapids, while cutting something large rapid moves speed can mean a lot on you machining time. also I think 18 or 36 is a too large reduction for stepper, for a servo it would be ok. Look no further than 7.2
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#4
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I must understand that a 7.3 geared motor will work well at 4 IPM ??
Thanks |
#5
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What is the 7.2 geared motors speed range (IPM) used in mechmates without problems .
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#6
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Have you priced the large pump that generates the pressure for the waterjet? These things are quite expensive even second hand ones. Waterjets are extremely useful machines and it would be great to see a homemade one, but a lot of people have started looking and were quickly turned around due to the costs involved in pumps and pipes and abrasive heads.
Building one would be a lot cheaper than buying though. Daniel |
#7
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Welcome,
This may turn out to be a very interesting build. Please post plenty of pictures of your progress. Bryan |
#8
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to answer that you need to know the following
1) weight of the mechanism the stepper motor is driving 2) the cutting resistance force of what ever you use at the cutting end 3) acceleration requirement. Or you can build one & test it out. |
#9
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Especially on how you keep the water out of the motors and electronics
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#10
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Quote:
Thanks. |
#11
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I think the real issue here will be the heat. If you derate the motors per the spec here and do not go over 39volts (You could go less since your machine is going to be slow on purpose). I think they will handle this no problem. I also agree the bigger issue will be making sure the system stays dry. Really just need to be splash proof.
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#12
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Quote:
Thanks |
#13
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Guillermo please read this whole topic on selecting motors
http://www.mechmate.com/forums/showthread.php?t=1114 almost everything will be clear to you then, then if you have questions after that please post them we will be all glad to answer as best as we know. Regarding the water protection here is some thought: http://www.homanndesigns.com/store/i...roducts_id=107 Its the nema23 mount but it should be no problem to make something similar to it for nema34 size motors we use. |
#14
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I think you don't need gear reductions for a waterjet machine, the motors only task would be to move the gantry as there are no other cutting forces involved.
Pablo |
#15
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Quote:
If you really wish to optimise to that extend, you should look at your PC speed & work backward to get the highest reduction ratio. BTW, the gear box isn't the only factor governing the overall reduction ratio, the pinion plays a huge part in it too. BTW, do you know what is the vertical force (reaction force of the cutting jet)? you may want to be careful of gantry lifting off the rail with too light a gantry. |
#16
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Quote:
Thanks |
#17
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Due that i dont need to vary head height while cutting i am going to use a manual Z axis.(no motor in z axis) Referring to the motor, my intention is to change as little as possible the configuration (pinions, motors, drivers, bob, power sourse etc) already proven in the machmate comunity. But my intuition takes mi to think that leaving everything the same and using a higher gear, i will get lowers RPMs in the shaft using the same motor RPMs all you have proven that works using with 7.2 : 1 geared motors. Anyway i am going to backward work. Thank |
#18
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Quote:
Thanks |
#19
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Guillermo,
I like your manual Z-axis approach. simplicity at it's best. ![]() Just though you might want to know this; My Z-axis assembly which is ball screwed weighs about 26lb, so your idea should work well with the "standard" MM hardware even with direct drive. ![]() Gearbox is good for multiplying torque as well as backlash error, hence, do weigh your options rationally. I think you are good to go with your water-jet plan just by going with the "standard" MM configurations except for the water-proofing part. |
#20
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Quote:
Thanks Mike |
#21
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Great to hear that this maybe the first homemade waterjet i've seen come to fruition. Whats your thoughts on the water bed, how large will your storage well be and how do you plan to transfer water between the two wells of water to allow the submerging of parts when needed.
Daniel |
#22
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"Regarding the water protection here is some thought:
http://www.homanndesigns.com/store/i...roducts_id=107 Its the nema23 mount but it should be no problem to make something similar to it for nema34 size motors we use." There are "dust proof" nema 34 motors on the market already too, which have the sealing backshells for the motors already attached. They aren't a proper IP67 water proof but will protect the motor form the occasion splash which is all you should have. Daniel Last edited by twistedfuse; Tue 12 July 2011 at 17:38.. Reason: Wrong quote |
#23
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NEMA 34 STEPPER MOTOR 1200 oz-in, ½” Shaft with a flat,, $159.95
Water, Dust proof KL34H2120-60-4A-IP65 This motor is IP65, which means it is (6) dust proof, (5) means water resistant to direct spray. I use this motor on a washing machine in the textile mill with a 1700PSI back spray soaking it all day long - no issues. It's not the smoothest motor at high speed, but in the 50RPM range - nice response with the Gecko G203V. Good luck. |
#24
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Quote:
I would appreciate If someone in the forum have information on this topic. Thanks Daniel. |
#25
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Quote:
Thanks Sean. |
#26
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One of the waterjet machines that i've seen was constructed quite strong, i think i may even remember that a re-enforced and thickened slab was needed, but the base was two separate tanks with a high flow bi-directional pump connected between them with a simple controller attached to move water between the two which changed your level. I have even seen one which used cylinders to store the top-up water. Biggest thing i can think of is there is a minimum distance to dissipate the energy of the water jet which prevents it wearing out the base of your tank.
Daniel |
#27
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Quote:
Hi Daniel, here is a sketch of a simple way i think could work the water level changer. It will work with an air compressor (that is part of allmost every workshop) and 2 manual valves. I would apreciate coments. Thanks Daniel. |
#28
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Very interesting way of doing it, but should work a treat. Look forward to seeing it in action.
Daniel |
#29
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Hello Guillermo, how is the process on the waterjet project? I would love to build one too! Mike.
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#30
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Hi Mike, i will probably start with the project in the middle of next year. I am in order for any information you need.
Guillermo. |
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