Jewelery magnetic polisher - Handmade by CMS

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#1 18 Sep 2020 19:13

About three months ago a friend asked me if I would build a magnetic polisher for his friend jeweler. I asked what is it what is it? A longer discussion developed here, an exchange of a few e-mails / sms with links and I already more or less knew what a machine it was.

The general principle of operation is simple. We have a spinning "plate" on which four strong neodymium magnets are mounted. Two of them are placed close to the outer edge of the plate and directed upwards with the N pole, and the other two are close to the center of the plate and directed upwards with the S pole. This creates a kind of rotating magnetic field wave which alternately attracts and repels the material . And the material is needles ... But more on that later.

I will not write here about all the difficulties and problems encountered, because there was so much that the construction took 3 months instead of the planned 2-3 weeks.

I will briefly describe the resulting device and share photos. Maybe it will be useful to someone in the future. The cost of the part plus unexpected expenses is about PLN 1800 plus labor. In total, about half of what you have to pay for a similar factory polisher.

Now it's time for some construction photos, because that's what DIY is all about.

It was the plate.

Here is the engine that turned out to be a total failure and had to be reworked to 3-F. For this I am proud of the thread in the shaft. As I couldn't pull off the pulley in any way, I drilled and threaded the motor shaft. Not having taps for blind threads.

Bottom of the housing and engine mount.

And here is the engine itself with a plate.

The work is moving forward, you can already see some outlines of the whole.

Closer to the final ...

Preliminary design of the front panel made of corrugated cardboard with a scalpel.

And here puttying ...

More putty and primer.

In the meantime, a front panel made of plexiglass was created, the inscriptions are engraved to a depth of 0.5 mm on a laser plotter and filled with nitro varnish.

This is what it looks like inside.

And so from the outside.

I am not going to post any diagrams or other documentation here, because they have not been created, and I will not create documents on purpose, since the machine is already at the customer's.
If someone is kumaty and needs such a machine, he will build it. After all, three months ago I didn't even know what it was ...

I just want to share some photos of the construction. Usually, I don't present my designs, even those of a high standard, because I don't have time for it. But this is the first time I have seen a device / machine of this type and this is the only reason why I am willing to share this construction with you. Because it's interesting.

The final result.
As I mentioned, I will not describe the vicissitudes of the entire construction, because it would take as long as the construction itself. You have pictures to see and read, a few sentences of text.

Maybe I will mention the security features.
If the motor housing exceeds 50 ° C (which did not happen during the tests), the fans will start.
If for some reason (despite the fans running) the motor reaches 85 °, the power to the inverter will be disconnected (the fans will, of course, remain powered).
And there is also an ordinary 20mm glass fuse.

At this point, I would like to thank my colleague BESTLER for this
any technical assistance and encouragement in the moments when I already doubted this project.

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CMS wrote 7633 posts with rating 2101, helped 193 times. Live in city Warszawa. Been with us since 2004 year.
#2 18 Sep 2020 22:34

Tomek515 Tomek515

Level 23

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#2 18 Sep 2020 22:34

A foreigner ordered it from you or are Polish subtitles out of fashion?
Don't take it as an attack because many criticize - whatever the problem, I just don't like getting English everywhere, even where there's no need.
"so American - better"
#3 18 Sep 2020 22:47

zulugula zulugula

Level 19

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#3 18 Sep 2020 22:47

You haven't written what these "needles" are, the concept is so simple that "why didn't I think of it myself".
If I ever needed a polisher, it is either a vibrating polisher that shakes and turns itself on or just such a patent.
Made almost like from the factory.
#4 18 Sep 2020 22:50

robokop robokop

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#4 18 Sep 2020 22:50

However, you did not take good advice. Rewinding the washing machine motor to three-phase in order to push it with an inverter - nonsense, technical and economic. For the cost of rewinding, you would have 2 used 0.18kW three-phase motors and there would be more for the turner to remake the axle. A better solution - commutator motor, speed easily regulated by voltage. Using the motor from the washing machine, with tacho feedback, you would have almost 100% torque throughout the speed range. The whole thing would be much smaller and lighter. And definitely 3 times cheaper.
#5 18 Sep 2020 22:58

Matheu Matheu

Level 24

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#5 18 Sep 2020 22:58

CMS , you write that there was a problem with removing the pulley.

Have you tried to use something like this (called bearing puller ):

(I don't know - maybe you know it and it didn't help, or maybe - it will be useful to someone else?)

greetings
- MaciekM
#6 18 Sep 2020 23:09

robokop robokop

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#6 18 Sep 2020 23:09

One more very important thing. The disc with magnets sticks to the motor axis on the screw - with a right-hand thread. When switching to "left" it will unscrew ...
#7 18 Sep 2020 23:43

Kajox Kajox

Level 18

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#7 18 Sep 2020 23:43

Do you need high turnover? I would use the hoverboard engine if the engine revs higher, for example from punto power steering, for example, drivers can be bought in good money, engines rather also available without any problems.
#8 19 Sep 2020 08:08

zgierzman zgierzman

Level 31

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#8 19 Sep 2020 08:08

I miss the info about "needles". In the video, it looks like metal shavings.
Isn't this motor - probably several hundred watts - too big for mixing a handful of shavings?

robokop wrote:
Using the motor from the washing machine, with tacho feedback, you would have almost 100% torque throughout the speed range.

Recently I was playing with the Chinese controller as shown in the picture and the washing machine motor.

For $ 10 hardware, the speed control works fine, but I haven't been able to load the motor with a solid torque. Have you had the opportunity to check something like this in practice?
#9 19 Sep 2020 09:13

ArturAVS ArturAVS

Moderator HP/Truck/Electric

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#9 19 Sep 2020 09:13

robokop wrote:
Rewinding the washing machine motor to three-phase in order to push it with an inverter - nonsense, technical and economic

I fully agree.

robokop wrote:
A better solution - commutator motor, speed easily regulated by voltage. Using the motor from the washing machine, with tacho feedback, you would have almost 100% torque throughout the speed range. The whole thing would be much smaller and lighter. And definitely 3 times cheaper.

In addition, the controller on the TDA1085C uses a tacho (a system specially for this purpose) and you have a very wide range of regulation (from several hundred to several thousand RPMs with torque retention).

CMS wrote:
As I couldn't pull off the pulley in any way, I drilled and threaded the motor shaft.

Marcin, you had to heat this circle. Overall, the structure is interesting and quite unusual.
#10 19 Sep 2020 09:55

CMS CMS

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#10 19 Sep 2020 09:55

Tomek515 wrote:
A foreigner ordered it from you

Yes.
More precisely, one of the contracting authorities is not a Pole.
However, the subtitles are in English because they are shorter and it was easier to fit.

zulugula wrote:
You haven't written what these "needles" are

Type in google "polishing needles" and you will find. They come in a variety of sizes.
First link:
https://alco.com.pl/igly-nierdzewne-0-5-mm,id1440.html

zulugula wrote:
Made almost like from the factory.

Thank you, I tried my best.

robokop wrote:
However, you did not take good advice. Rewinding the washing machine motor to three-phase in order to push it with an inverter - nonsense, technical and economic. For the cost of rewinding, you would have 2 used 0.18kW three-phase motors and there would be more for the turner to remake the axle. A better solution - commutator motor, speed easily regulated by voltage. Using the motor from the washing machine, with tacho feedback, you would have almost 100% torque throughout the speed range. The whole thing would be much smaller and lighter. And definitely 3 times cheaper.

I listened to the advice and took it to heart. I will certainly use them in future constructions.
Here, however, the replacement of the engine at the stage when it became apparent that it was not suitable was too late. It was more profitable to pay PLN 300 for rewinding than to fit the existing structure to another engine.

Would it be 3 times cheaper, I dare to doubt. The engine cost a hundred, winding 300. How much would I save on another engine, and how much time would I waste to fit. If I had consulted with you earlier, when we were not at an advanced stage yet, we would probably have used a different engine and would have built the rest for it, but I wouldn't have saved a lot either.

Matheu wrote:
Maybe you tried to use something like this (known as a bearing puller):

I tried to remove the pulley, exactly with the puller as shown.

robokop wrote:
One more very important thing. The disc with magnets sticks to the motor axis on the screw - with a right-hand thread. When switching to "left" it will unscrew ...

I thought about it. Between the disc and the pulley, there is a silicone washer of the pulley diameter. After 6 hours of testing, nothing loosened. And as if you can always drip blue thread glue.

zgierzman wrote:
I miss the info about "needles". In the video, it looks like metal shavings.

I gave the link a few sentences above.

Added after 33 [minutes]:

ArturAVS wrote:
Marcin, you had to heat this circle. Overall, the structure is interesting and quite unusual.

I can see that we were writing at the same time.
I was heating, but the main problem was that the shaft was immobilized so that it would not spin when I pressed against the puller.

As for the motor, it was a coincidence that we owned one, and it was also coincidence that it operated with an inverter. Only during the final tests, when the machine was about to go to the customer, it turned out that it works, but not for more than a few minutes, and then the inverter crashes. The engine turned out to be damaged, and since everything was already built to the size of this particular engine, it was more profitable to spend 300 than to convert the entire structure to another engine.

So let's finish the engine topic. I know that there are better solutions and I will use them in the future.
However, there is a plus in using this engine - I gained a lot of useful knowledge ... For example, that such an engine is not suitable for such an application . I learned how to configure inverters and that the instructions from them are written in such a way as not to make it easier to use, and certainly not to someone who has to deal with it for the first time.
I also learned (experimentally) that the French engine cannot be connected via autotrafo, i.e. it can be connected, but I do not recommend switching it on.

It's like the joke when the shepherd was washing the cat.
The tourist looks and says, Baco does not wash the cat.
It is washed.
In the afternoon the tourist returns, the shepherd is still sitting, but the cat is dead.
The tourist says, Baco, I said that the cat is not washed.
It is washed, but it does not twist.
#11 19 Sep 2020 10:32

vodiczka vodiczka

Level 43

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#11 19 Sep 2020 10:32

CMS wrote:
And the material is needles ... But more on that later.
There is no later which is a pity. Instead of a lot of photos (in my opinion, 1/3 of what my colleague posted is enough), I would prefer a few sentences explanation about the advantage of the magnetic polisher over the traditional one.
#12 19 Sep 2020 11:14

robokop robokop

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#12 19 Sep 2020 11:14

.
CMS wrote:
Would it be 3 times cheaper, I dare to doubt. The engine cost a hundred, winding 300. Well, how much would I save on another engine,
So a total of 400, - These motors from washing machines in scrap yards are going to get for 20 PLN for 30 PLN. New Besel engine 0.18kW - PLN 200- 300. So you already have half. Used 0.18kW motor - from a gear motor or fan below PLN 100 - that is 1/4 of your price. Commutator motor - used around PLN 50. Phase regulator on the triac - let's say another PLN 50. With the efficiency of the magnetic coupling below 20%, even no speed stabilization would be needed, the motor would roughly have the speed directly dependent on the voltage.

On the commutator motor from the washing machine and the phase regulator, I made a drive for the honey centrifuge. With heavy, full frames, it spins slowly, it accelerates as the mass of them loses - which is even beneficial for throwing out the remains "to the bottom".
#13 19 Sep 2020 11:14

CMS CMS

Administrator of HydePark

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#13 19 Sep 2020 11:14

Needles you have a few posts above in the link.
There is nothing to write about them.

vodiczka wrote:
I would prefer a few sentences explanation about the advantages of the magnetic polisher over the traditional one.

Have you read the description?
I don't know anything about it. When a friend asked if I would build it, I had no idea about the existence of such devices. I have no comparison with any other polisher, so I don't know what their advantages and disadvantages are.

I just designed and built what they asked me for.
The customer is satisfied, the cash register agrees. Soon I will be making a jewelery vulcanization press for him. Even a few days ago I didn't know what it was.
#14 19 Sep 2020 11:19

robokop robokop

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#14 19 Sep 2020 11:19

CMS wrote:
Soon I will be making a jewelery vulcanization press for him.

With both plates heated, or only the bottom plate? Pneumatic pressure? Because I have nice actuators
#15 19 Sep 2020 11:24

CMS CMS

Administrator of HydePark

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#15 19 Sep 2020 11:24

robokop wrote:
.
CMS wrote:
Would it be 3 times cheaper, I dare to doubt. The engine cost a hundred, winding 300. Well, how much would I save on another engine,
So a total of 400, - These motors from washing machines in scrap yards are going to get for 20 PLN for 30 PLN. New Besel engine 0.18kW - PLN 200- 300. So you already have half. Used 0.18kW motor - from a gear motor or fan below PLN 100 - that is 1/4 of your price. Commutator motor - used around PLN 50. Phase regulator on the triac - let's say another PLN 50. With the efficiency of the magnetic coupling below 20%, even no speed stabilization would be needed, the motor would roughly have the speed directly dependent on the voltage.

On the commutator motor from the washing machine and the phase regulator, I made a drive for the honey centrifuge. With heavy, full frames, it spins slowly, it accelerates as the mass of them loses - which is even beneficial for throwing out the remains "to the bottom".

We wrote simultaneously.
Now I understood that these 3 times cheaper was for the engine itself. I understood that you are talking about the whole.
At the cost of the whole, these PLN 300 was a fraction.

Added after 1 [seconds]:

robokop wrote:
.
CMS wrote:
Would it be 3 times cheaper, I dare to doubt. The engine cost a hundred, winding 300. Well, how much would I save on another engine,
So a total of 400, - These motors from washing machines in scrap yards are going to get for 20 PLN for 30 PLN. New Besel engine 0.18kW - PLN 200- 300. So you already have half. Used 0.18kW motor - from a gear motor or fan below PLN 100 - that is 1/4 of your price. Commutator motor - used around PLN 50. Phase regulator on the triac - let's say another PLN 50. With the efficiency of the magnetic coupling below 20%, even no speed stabilization would be needed, the motor would roughly have the speed directly dependent on the voltage.

On the commutator motor from the washing machine and the phase regulator, I made a drive for the honey centrifuge. With heavy, full frames, it spins slowly, it accelerates as the mass of them loses - which is even beneficial for throwing out the remains "to the bottom".

We wrote simultaneously.
Now I understood that these 3 times cheaper was for the engine itself. I understood that you are talking about the whole.
At the cost of the whole, these PLN 300 was a fraction.
#16 19 Sep 2020 11:28

vodiczka vodiczka

Level 43

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#16 19 Sep 2020 11:28

CMS wrote:
Have you read the description?
I don't know anything about it.
Do not take my entry as a complaint, but since you wrote in the first post that about needles later, I thought that you would go deeper into the topic. You did not have to.
The principle of operation is completely different than the "felt polisher". Found on the net:
The idea of operation of magnetic polishers is based on the creation of an alternating magnetic field. Under the influence of magnetic forces, the micro needles immersed in the supporting fluid are set in a vortex motion. Cleansing takes place through the intensive movement of stainless steel micro needles along with the processed details.
It is more like rotary abrasive machining, i.e. polishing by tumbling.
#17 19 Sep 2020 11:31

robokop robokop

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#17 19 Sep 2020 11:31

vodiczka wrote:
that about needles later, I thought you would go deeper into the topic. You did not have to.
This is a type of vibration polisher - the workpiece is polished by impact / abrasion by small wear-resistant elements.
#18 19 Sep 2020 11:32

CMS CMS

Administrator of HydePark

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#18 19 Sep 2020 11:32

robokop wrote:

CMS wrote:
Soon I will be making a jewelery vulcanization press for him.

With both plates heated, or only the bottom plate? Pneumatic pressure? Because I have nice actuators

Heated top and bottom. Manual pressure, but if you have actuators, who knows ...
The polisher was also supposed to be simple at first, and a beautiful, almost factory product came out.
#19 19 Sep 2020 11:33

robokop robokop

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#19 19 Sep 2020 11:33

CMS wrote:
I understood that you are talking about the whole.
I wrote about the whole. A commutator motor would be cheaper - an expensive inverter would also fall off. So probably a thousand less together. For a hundred you would have a motor with a phase regulator.
#20 19 Sep 2020 11:40

CMS CMS

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#20 19 Sep 2020 11:40

The inverter was a lucky, because 86pln was a lucky (here a separate story)
#21 19 Sep 2020 11:53

DjMapet DjMapet

Level 43

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#21 19 Sep 2020 11:53

vodiczka wrote:
I would prefer a few sentences explanation about the advantages of the magnetic polisher over the traditional one.

In short, a traditional polisher is usually a tool for small jewelry manufacturers (and not only), who make small amounts (a few, a dozen or so), and various jewelry products.
Magnetic polishers are mainly used by producing jewelry items on a larger scale. If there are several thousand or even a few hundred small elements to be polished, doing it using traditional methods, it would take a lot of time.

Greetings.
#22 19 Sep 2020 13:19

gemiel gemiel

Level 25

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#22 19 Sep 2020 13:19

In such polishers, the plate with magnets should be well balanced so that the machine does not behave like a block shaker. Have you had trouble balancing your shield?
#23 19 Sep 2020 16:14

PPK PPK

Level 28

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#23 19 Sep 2020 16:14

A long time ago, a friend was doing such a polishing machine for a guest from Gdańsk, but without the rotating parts. Instead of rotating magnets (there were no neodymium ones yet), he installed TTL-controlled electromagnets, probably 74154 and transistors as drivers. Generator for 555 (with adjustable fill) and some series / BCD. There was a problem with induced voltage but it handled it with separate power supply and chokes ...... I am so in awe of your workshop work. I have always had problems with the housings .....
#24 20 Sep 2020 12:14

CMS CMS

Administrator of HydePark

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#24 20 Sep 2020 12:14

Buddy andrzejlisek, create your own topic, because your discussions have nothing to do with the polisher.

Added after 5 [minutes]:

gemiel wrote:
In such polishers, the plate with magnets should be well balanced so that the machine does not behave like a block shaker. Have you had trouble balancing your shield?

The plate itself is well balanced. Without load, the polisher does not vibrate and is almost silent.
On the other hand, placing a vessel with needles and the processed material makes the whole thing vibrate together with the table on which it stands. The needles also make a lot of noise. But the client said it was normal.
#25 27 Sep 2020 19:58

kilioo kilioo

Level 12

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#25 27 Sep 2020 19:58

Great idea. Have you verified it on larger dimensions?
#26 27 Sep 2020 20:07

robokop robokop

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#26 27 Sep 2020 20:07

CMS wrote:

The plate itself is well balanced.
Basically, it can only be balanced roughly - the engine does not reach the nominal speed, but much lower - otherwise, once the rubbing needles would generate a lot of heat, the centrifugal force would lead them against the walls of the box, instead of the entire volume.
#27 28 Sep 2020 18:24

CMS CMS

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#27 28 Sep 2020 18:24

Rob, I limited the speed (in the inverter settings) to a maximum of 2400rpm, because at the nominal 3400rpm, while the plate itself caused a slight brumm (but not vibrations, only audible), with the needles on board there was such a forage harvester that the microwave was standing on the same (the metal table) as the polisher wanted to jump off it.
Only then did I find out that the needles are flooded with water with dishwashing liquid, which significantly reduces vibrations and heating the whole thing).

robokop wrote:
otherwise the rubbing needles would generate a lot of heat,

Not that much, as I found out experimentally when, not knowing yet that water was pouring there, I polished a few elements for 6 hours. They were warm, but not above 40 ° C.
#28 30 Sep 2020 19:55

anski anski

Level 10

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#28 30 Sep 2020 19:55

Cool design, only these inscriptions. Can't you speak Polish?
#29 30 Sep 2020 21:08

CMS CMS

Administrator of HydePark

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#29 30 Sep 2020 21:08

CMS wrote:
Tomek515 wrote:
A foreigner ordered it from you

Yes.
More precisely, one of the contracting authorities is not a Pole.
However, the subtitles are in English because they are shorter and it was easier to fit.
#30 06 Oct 2020 15:02

inincjusz inincjusz

Level 10

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#30 06 Oct 2020 15:02

Cool, this polisher congratulates your persistence in construction.
So I thought whether instead of rotating magnets to use electromagnets with magnetic lenses and to control them in turn, that's the thought.
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Jewelery magnetic polisher - Handmade by CMS