MechMate CNC Router Forum

MechMate CNC Router Forum (http://www.mechmate.com/forums/index.php)
-   Introduce yourself and start planning (http://www.mechmate.com/forums/forumdisplay.php?f=88)
-   -   Waterjet Project - Puerto Ordaz Venezuela (http://www.mechmate.com/forums/showthread.php?t=3442)

Guillermo Sun 10 July 2011 14:16

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.

Guillermo Sun 10 July 2011 15:20

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 .

danilom Sun 10 July 2011 15:24

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 :)

Guillermo Sun 10 July 2011 15:29

I must understand that a 7.3 geared motor will work well at 4 IPM ??

Thanks

Guillermo Sun 10 July 2011 16:42

What is the 7.2 geared motors speed range (IPM) used in mechmates without problems .

twistedfuse Sun 10 July 2011 17:09

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

bolingerbe Sun 10 July 2011 17:45

Welcome,

This may turn out to be a very interesting build. Please post plenty of pictures of your progress.

Bryan

KenC Sun 10 July 2011 23:09

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.

jehayes Mon 11 July 2011 01:36

Especially on how you keep the water out of the motors and electronics:)

Guillermo Mon 11 July 2011 06:22

Quote:
Originally Posted by KenC View Post
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.
Hi Ken, in waterjets, the cutting head dont generates lateral forces or cutting resistence, and cutting speeds ranges between 4 and 30 IPM. That allows the use of a lither gantry,and the need of less acceleration. the quetion comes because i was thinking in the use of a 1.18 or 1.36 geared motor sacrificing speed that dont need and winning torque and resolution.
Thanks.

MetalHead Mon 11 July 2011 06:29

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.

Guillermo Mon 11 July 2011 06:45

Quote:
Originally Posted by MetalHead View Post
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.
Hi Mike. you are saying that i most stay with the 7.2 :1 geared motors end do not go over 39 Volts ??

Thanks

danilom Mon 11 July 2011 06:49

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.

PEU Mon 11 July 2011 06:51

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

KenC Mon 11 July 2011 07:03

Quote:
Originally Posted by Guillermo View Post
Hi Ken, in waterjets, the cutting head dont generates lateral forces or cutting resistence, and cutting speeds ranges between 4 and 30 IPM. That allows the use of a lither gantry,and the need of less acceleration. the quetion comes because i was thinking in the use of a 1.18 or 1.36 geared motor sacrificing speed that dont need and winning torque and resolution.
Thanks.
30ipm is slow... very slow... I seldom/never got below 50ipm with my work here. & I seldom allow jogging speed over 600ipm.
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.

Guillermo Mon 11 July 2011 17:53

Quote:
Originally Posted by twistedfuse View Post
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
Hi Daniel, i am aware about all expenses involved in the proyect. If everithing goes well, i most be starting the building at the end of the year.
Thanks

Guillermo Mon 11 July 2011 19:54

Quote:
Originally Posted by KenC View Post
30ipm is slow... very slow... I seldom/never got below 50ipm with my work here. & I seldom allow jogging speed over 600ipm.
If you really wish to optimise to that extend, you should look at your PC speed & 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.
Hi Mike, according to my researchs, the up vertical force generated by the cutting head is very small. (about 10 pounds). The gantry should be designed to suport the cutting head + abrasive hopper (about 22pounds).
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

Guillermo Mon 11 July 2011 20:04

Quote:
Originally Posted by danilom View Post
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.
Hi Danilo, i really appreciate avery coment all you considere relevant to my proyect.
Thanks

KenC Tue 12 July 2011 00:49

Guillermo,
I like your manual Z-axis approach. simplicity at it's best. :D
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.

Guillermo Tue 12 July 2011 06:40

Quote:
Originally Posted by KenC View Post
Guillermo,
I like your manual Z-axis approach. simplicity at it's best. :D
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.
Wellcome every pro and cont coments

Thanks Mike

twistedfuse Tue 12 July 2011 17:34

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

twistedfuse Tue 12 July 2011 17:37

"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

smreish Tue 12 July 2011 17:47

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.

Guillermo Tue 12 July 2011 19:33

Quote:
Originally Posted by twistedfuse View Post
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
Hi Daniel, that is something i am still not clear, but according tu my research, the way it works is with some type of bladder inside the tank.
I would appreciate If someone in the forum have information on this topic.

Thanks Daniel.

Guillermo Tue 12 July 2011 19:51

Quote:
Originally Posted by smreish View Post
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.
Hi Sean, this motors could be a good option. What do you think about this motors working direct drive at 2 or 3 RPM or should i use some gear or belt reduction. Remember that my cutting speed ranges between 4 and 30 in/min.


Thanks Sean.

twistedfuse Tue 12 July 2011 21:04

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

Guillermo Thu 14 July 2011 10:59

1 Attachment(s)
Quote:
Originally Posted by twistedfuse View Post
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

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.

twistedfuse Thu 14 July 2011 16:35

Very interesting way of doing it, but should work a treat. Look forward to seeing it in action.

Daniel

mike nelson Sun 13 November 2011 23:14

Hello Guillermo, how is the process on the waterjet project? I would love to build one too! Mike.

Guillermo Mon 14 November 2011 15:42

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.


All times are GMT -6. The time now is 23:13.

Powered by vBulletin® Version 3.8.3
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.