How would you build it

[scroughstock]

I am new here so I apologize if this is in the wrong place.

Here is the plan, To build a tool with a DC electro magnet that will plug into a standard 110 outlet. The electo magnet that will turn on/off up to 250 times per second.
The top speed would be the 250/sec and the lowest point would be about 0/sec with no trigger pull. I want to put this into a resistance type trigger. The less trigger pull the less on/off cycles. I am just pulling numbers out of my hat, but I would guess that the magnet will need a minimum of 10A.

I have absolutely no idea what I'm doing with this kind of stuff, but I was told I would need a 555 IC. What I read it makes sense, but I don't know what else I would need to make this work

 

[blueroomelectronics]

What's it for?

 

[scroughstock]

The electro magnet will be driving a piston with a permanent magnet on the other side. It will be like a miniature hand hled jack hammer. The piston will weigh somewhere around 1/2 ounce.

 

[blueroomelectronics]

OK, what's the purpose of the machine? Why an electromagnet, why not just a spinning wheel and shaft like a tattoo gun.

 

[scroughstock]

The tool will be used for metal engraving and line cutting is steel. It is not the same type of engraver as a dremel tool. It is designed to mimick a chisel and hammer only about 250 times faster. The type of design you mention I had considered, but with size constraints I could not get a big enough motor. Also, any motor that I could get that kind RPM out of wouldn't handle the eccentric offset to drive the piston.

There is pneumatic versions of what I am trying to build, but nothing electric.

 

[blueroomelectronics]

Got a link to a commercial unit?

 

[scroughstock]

No I don't.
I know one uses air pulses to push down the piston and has a return spring. The problem with spring is that they can't handle the kind of strokes per minute that I want to produce.

The other company uses pneumatics as well, but I don't know how it works. I do know that they don't use a spring and they are able to acheive the strokes per minute.

I am trying to design the electric version so I don't have to carry an air compressor or bottled gas.

 

[Jaguarjoe]

The electro magnet will attract the piston which provides 1/2 of the stroke. What provides the other half of the stroke?

 

[scroughstock]

The electro magnet will actually drive and return the piston. The permanent magnet will have the same polarity as the elctromagnet. When the electomagnet is on the magnets will repel and drive the piston down. When the electromagnet switches off the iron core in the electromagnet will attract the permanent magnet and pull it up. If the iron and permanent magnet are not enough then I will put some permanent magnets with opposite polarity on the bottom of the piston.

I have everything worked out except the electronics part. I have not figured out out to get the magnet to switch at the speeds that I need to acheive.

 

[Mr RB]

It's not a trivial project. Motorised tools of that type use around a 400W motor, so you would probably need to build a driver circuit and coils all capable of maybe 300W+. Considering you need a h-bridge driver (to reverse the voltage to your coil) it won't be simple.

You may also need a fan to cool the coil, where motorised tools like this use a fan on the motor shaft.

 

[RMMM]

This is a bad design idea.

Basically you are building a coil gun that has its ammo attached.

A motor, on its side, with the chisel attached to a cam will give you the up-down strokes you want..at speed faster if you wish.

A spring return at the last 5% of the stroke will keep too much shock from the motor.

The problem with your idea, is you will need a guide to keep the chisel straight through its flight.

You cant use many metals because that will change your inductance and flux.

The motor on its side, cam, chisel.

Look up jail house tattoo gun.

You can use the exact layout, just larger parts.

 

[shortbus=]

Have you seen this? https://www.dremel.com/en-us/Tools/Pages/ToolDetail.aspx?pid=290-01+Tool Not a regular Dremel tool but a actual enraver, works at 7,200 strokes per minute.

 

[MrAl]

The electro magnet will actually drive and return the piston. The permanent magnet will have the same polarity as the elctromagnet. When the electomagnet is on the magnets will repel and drive the piston down. When the electromagnet switches off the iron core in the electromagnet will attract the permanent magnet and pull it up. If the iron and permanent magnet are not enough then I will put some permanent magnets with opposite polarity on the bottom of the piston.

I have everything worked out except the electronics part. I have not figured out out to get the magnet to switch at the speeds that I need to acheive.

Hello,


How much stroke are you looking to get? 0.01 inch, 0.05 inch, 0.10 inch, etc.,?

Also, did you look into regular engraving tools yet, like a small vibrating engraver?

 

[kinarfi]

Magnets and coil makes me think of the sonic care tooth brush by Phillips, It had 2 powerful magnets driven by by a coil and an arm attached to the brush. Maybe you could explore something like that.

 

[Joe G]

**broken link removed** how would this work.

 

[blueroomelectronics]

Looks like any other high speed Dremel tool. The OP wants some sort of hammer type device.

 

[Joe G]

never judge by looks


The 1011 Micromotor is ideal for stone setting applications, including channel setting and engraving techniques requiring reciprocating action.
The force of the impact of this reciprocating handpiece can be adjusted from light to full by turning the metal ring while the motor is off or running. The speed of the hammer action can also be varied from 0- 5,000 strokes per minute with the manual dial on the control box. or the optional foot speed control.

1011 Stone Setting/Engraving Micro Motor Kit includes the MH-011 Hammer Handpiece. Stock# 1080 Micromotor Stone Setting Kit $795.00

FM3545 Control and the H8-214 Graver Holder and other accessories sold separately and shown below. The MH-011 Hammer Handpiece comes with the 1011 kit.


ricating stroke from 0 to

 

[Joe G]

years ago i wanted one for engraving guns, this one is just one of many that are made. some are wayyyyy cheaper in price, check woodcraft and brownells for starters. i use a sub 100$ one at my job and it works fairly nice.