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[RockinUSA]

I am trying to construct a multi pan vibrating lap machine. I have purchased an 80w 110v 3600rpm concrete vibrating motor. When running the motor the grit and slabs in the pan gather to one side. I have tried to troubleshoot it by leveling the plate the motor is mounted to and by changing the orientation of the pan. It seems to be a direction issues with the vibrational force produced by the motor.

I was hoping someone might be able to give some insight as to how to change the direction of vibration so that the grit moves in the circular pattern required for lapping.

This is the Amazon link to the motor I purchased: GPOAS 80W Concrete Vibrator Vibration Motor Single Phase AC 110V 3600RPM,Aluminum Alloy Case Electric Asynchronous Vibrating Vibrators for Shaker Table(80W) https://a.co/d/5CjGvxu

I adjusted the counterweights and did not notice a difference.

[55fossil]

   Can we get a picture of the lap?   Could be easier if we see what we are trying to fix.  Great project.

[lithicbeads]

 A picture would help.These are slabs you are lapping? In my vibratoing flat lap the pan is supported on springs hung from a frame. Is yours?

[RockinUSA]

Photos include: motor, underside of plate, full assembly, an example of the grit mounding and the pans with the diameter.

I made some adjustments to the original. I realized the springs were too stiff and have since jury rigged a screen door spring to the eye bolts as suspension. That improved the sound output of the assembly and also seemed to lesson the severity of the mounding but only by a little. I also added the 2x4 to the underside of the plate as the plate was sagging on the ends. The motor is now mounted perpendicular to the plate. I was hoping the new mounting position would have a greater affect to the mounding but it has essentially stayed the same.

The 12" pans are mounted to the plate via four, 60lb magnets. The center plate mount is center the motor and the magnets are inlayed into the plate. The four other mount magnets are fastened/glued directly to the surface of the plate. They hold better than the inlay but don't seem to be strong enough to counter the vibrations. I understand that a magnets rating is for pull. The pans are galvanized steel feed pans for livestock. They have some flex but are thicker in guage than your standard sheet metal. Not very confident in defining or attempting to define it's actual guage.

I have since come to think that the pan is jumping. I have applied pressure to the pan during operation to see the effect and it appeared to have a positive effect. After considering this and the conventional manufactured vibralap  I suspect the pans need to be very firmly clamped to the plate. I understand that wood is not a good material for the plate. However, my solution is to cut out five 11" circles in a fitting OSB sheet and bolt that to the plate to clamp all the pans at once.

In summation, there are a lot of potential issues with my design but the most pressing is to get the proper movement of the grit slurry. Th :tongue:is project is trying to be as cost effective as possible. I have no prior understanding of vibration laps or the practicality of my "design". I am also constructing a 14" slab saw at the same time as this and to be honest I truly thought the vibralap would be the least of my concerns.

Am I wasting my time with this design? My plan is to see if it works and polish up as much as I can until the OSB is not reliable and purchase a steel plate. I can only run one tool at a time in my garage and would like to maximize the amount of slabs and grits I can run at one time.

[55fossil]

   McGyver would be proud!    My best idea is to put a slab in the pan of grit with water and turn it on. Then watch how the grit and slab move around. Start with a smaller grit, 220 or finer so it can actually get under the slab and start working right off.
    My laps, including a 24 inch all steel unit, were very partial to even the slightest tilt to the pan of grit. I would level the unit after it was running by watching where the water / slurry shifted too. The best lap will not work well if the pan is not perfectly level. If your springs are too light it will not stay level with a large piece of rough as it will tilt the pan when the rough moves too far to any side.

good luck

[RockinUSA]

Thank you for the positive feedback and motivation. I plan on upgrading the suspension system this weekend to try and find tune the leveling capabilities. I did some tweaking yesterday to no avail. I made a full diameter clamp for two pans and it doesn't seem to have had any effect.

The most troubling bit about the mounding is that it mounds to one side regardless of the level of the pans. If I tilt the plate so that the mound is definitively on the high side only the water moves downslope. The grit stays on that side, all mounded up.

Does anyone know how the magnets may affect the vibrational force direction?

[R.U. Sirius]

I wouldn't give up on this yet, but obviously you should be prepared to spend more time learning about and (re)designing the mechanics of your contraption.

The product page you linked to includes the image attached here, where we see the orientation of the eccentric weights. To ensure your pan vibrates strictly in the horizontal plane, I think this vibrator should somehow be mounted so its axis of rotation (its shaft) is perpendicular to the pan, not parallel as it is right now.
61hfcs.jpg (38.77 kB - downloaded 29 times)
Another issue then is the center of mass - with the heavy pan and rocks on top, and small vibrator with its weights mounted beneath the pan, there will be some rocking motion introduced that introduces the undesirable vertical component in the trajectory. Perhaps a counterweight mounted rigidly beneath the vibrator to bring the overall center of mass down into the vibrator region would help.

As you are making modifications to optimize your setup, I suggest trying to visualize the actual trajectory in operation. If you have a digital camera, set the exposure manually to 1s or so (even newer phone camera will let you do this). Adhere a dark sticker with a bright dot somewhere on the edge of the pan, and take a photo - the motion blur of the dot will show the trajectory of the pan. You can shoot from top and from the side to get a 3D idea about what your pan is doing!

Hope this makes sense... have fun, and let us know how it goes!

[RockinUSA]

Sirius,

Having the motor shaft perpendicular makes sense. I need to make the suspension easier to adjust and then will switch the mounting. I have since moved the motor to the topside of the plate. I ran it like that but couldn't ensure the plate was level. However, it didn't seem to make a difference. If the mounting switch-up doesn't work then I will move the motor back to the underside and try to rig up a fixed counterweight to adjust the gravity center. My plate is not truly square along with my eyebolt mounts. I have been relying heavily on my ability to make the plate level from the suspension adjustments.

To clarify, you are suggesting that if the motor is not on center as accurately as possible that this would affect the output direction?

That you for your response. I feel that I am only a few troubleshooting sessions away from figuring this out.

[55fossil]

    More questions than answers....   Have you tried putting a good size slab in the pan and see how it moves with a little water and no grit?  I would be interested if the slab orbits in a circular motion when your lap is running. So, even if the grit wants to mound up the movement of slabs in the pan would move the grit around as well. So, if your pan is level and the water settles evenly in the pan it may still work as is. just a thought.

[R.U. Sirius]

I don't think having the motor perfectly centered in the horizontal plane is a critical issue here, though it might help with leveling the pan.

I would first try mounting the motor so its shaft is perpendicular to the pan, so vibration takes place in the horizontal plane.

Kudos for taking on this DIY project, it's certainly not trivial... Looking forward to seeing more!