I think the motor winding might be acting as a current filter. Adding a capacitor across the motor terminals might help with the sparking. I think the solenoid that drew only 700ma would still work. Adding a power resistor in parallel with the solenoid windings would allow you to trim the current needed. For example 700ma will flow through the solenoid and 300ma through a selected resistor will give you a total current of 1 amp.
Physics doesn't work like you think it would work ;-) Remember you create a (sort of) voltage divider with the spark gap by adding a ohmic resistor in parallel to the motor. Also with the capacitor you add even more complexity to your circuit. Try it out if you think you know better and prove me wrong, but just selecting a motor that fits your needs is the more simple way and this series of spark erosion is about simplicity.
It should be possible to run the engraving voltage separate from the motor voltage to give you more adjustment. One voltage could trigger a transistor or solid state relay to turn the other voltage on and off. You could experiment with constant current supplies and with constant voltage supplies to get the performance your after.
you always make interesting things , thank you for the inspiration how about using a motor to turn a helmet into a speaker? frequency range , response , portability ,stereo possibility , power consumption ,attaching it and removing it , are the questionable parts
i know what im going to be trying next time i break a tap in titanium... never thought of doing this... lol. yet so simple. um. the motor has not just resistance but also inductance. the higher power motor will have lower DC resistance, but they also have much lower inductance, generally having a low turn count. do the maths on the numbers you gave, and youll see the resistance and the inductance as it doesnt quite follow ohms law until saturation. motors have sweet spots, torque variations. the commutator and brush and pole alignment all plays a role... maybe just use a BLDC on one phase? this is a hard one. is the sparking necessary or not? i think it is but its the nature of that arc... i feel it needs to be a "ringing", much like AC/DC tig welding gives a "cleaning" action... except then you want to wash the arc and resultant byproducts away. iunno. havent played with edm much... this reminds me of two similar non standard uses... making a servo, and reverb units. servo. feed, it with a PWM signal, against a spring. still, i think a standard "bell ringer" type buzzer would work just as well if not better.
Of course, there is more than just ohmic resistance to consider. This is a series on making (sort of) EDM, looking for simple solutions. That "bell ringer" setup has been treated in previous videos. DC motors might be more commonly available than the old school door bells ;-) In the iteration currently in development I have implemented a microcontroller. Although I do nothing but "replicate" a Wagner Hammer with that setup, yet, a microcontroller offers real time observation and feedback control of what is actually going on. I will do experiments to see whether maintaining the spark as long as possible leads to better results or making and breaking contact at high frequency is to go for. There is still a lot to be told about a circuit composed of an inductor an a spark gap. Thanks for sharing your thoughts and don't forget to share the results you get with your setup!
Very entertaining series. I wonder if you can get a higher current through the motor with a reasonably large capacitor on the output to allow the current to discharge on contact and rely on the inductance of the coil to limit it through the motor iteslf.
Well that's what's happening. In fact the computer power supply has an output capacitor. Adding another one won't change that much. You need a power supply that can deliver high current.
So it seems like the issue with these is that the motion of the motor/solonoid is tightly coupled with engraving power. An upgraded version would separate the power for engraving and the power for moving the wire, so in this case you could sense the current through the engraving wire to trigger a different power source for the motor. Then both are driven at exactly the right power
There is also wear on the tungsten tips. The working principle is different from TIG welding. Making contact with the workpiece quickly wears the pointy tip as shown in a previous video of my EDM series.
@@HomoFaciens I may not have been clear on my meaning , the tungsten should have a prolonged life compared to other metals , and the mineral oil is used in carbon arc erosion i'm sure , I went to college with a guy who needed to get college certificates to work in his dads company doing carbon arc erosion , I watched some stuff about it , we were studying for our electronics technician certificates ,1st year , the oil used is purer than water , mineral water might work well or reverse osmosis water to avoid conduction into the cooling fluid by mineral contamination.
There isn't "the electrode material" nor "the fluid". As the cooling / flushing fluid must have a low conductivity, oil is in general better than water. But also, messing with oil in your (hobbyist) machinery isn't as comfortable as using deionozed or even tap water. Also discarding the water from time to time is easier than implementing a filter system. Another yes, tungsten is more resistant to wear in EDM machining because of its high melting point, but there are exceptions from that rule: Heat conduction is another property that reduces wear. Same as with the water or oil decision, brass is cheaper, has a relative low wear and is for those reasons often used. In another video of that series I had a (very) quick look at different electrode materials: ua-cam.com/video/rS5600spxEQ/v-deo.html I will carry out more experiments in the future - stay tuned!
@@HomoFaciens As for a contact conductor you could use a pointed carbon rod,as again for the oil method ,some of the comments by other watchers mentioned an interest opposed to laser etching and i thought i'd add what i knew to work in industrial environments. Either way, i myself am interested in this method of engraving cast alloy and steel than acid etching,i need to make a cnc controler first though. Very informative video as always. All the best.
As with the making and braking contact in my setup, the conductivity of the fluid really doesn't matter that much and tap water works fine. It is simple and cheap and so definitely worth experimenting with. Thanks for sharing your thoughts!
Ok , so how about using a Tungsten welding electrode for the engraver tip. That would solve the erosion of the engraver while it's engraving the base metal ??
The tip of that electrode will erode same as the tungsten wire, since it is the same material. The electrode tip will become blunt, resulting in wider lines. The pro of the 0.2mm wire is, that the diameter stays constant even if the tip erodes. Welding electrodes are used in a different way: They are meant to maintain a plasma while with the Wagner hammer there are sparks formed and cut off at a high frequency. In an earlier video of this series I made use of a sharpened tungsten electrode: ua-cam.com/video/rS5600spxEQ/v-deo.html
Yes, that works in general, but you eventually confuse the maximum current "fuse" of the PSU which might cause damage of your power supply. Spark erosion works with high currents so it is a risk.
A Great idea, something I would like to have a go at.
...and don't forget to share your results.
This could be a very cheap substitution for a laser to engrave metals.
I'm tempted to build one, and mount it on my large CNC :)
...and don't forget to share the result you get.
Fun to watch this project in progress!
I think the motor winding might be acting as a current filter. Adding a capacitor across the motor terminals might help with the sparking.
I think the solenoid that drew only 700ma would still work. Adding a power resistor in parallel with the solenoid windings would allow you to trim the current needed. For example 700ma will flow through the solenoid and 300ma through a selected resistor will give you a total current of 1 amp.
Physics doesn't work like you think it would work ;-)
Remember you create a (sort of) voltage divider with the spark gap by adding a ohmic resistor in parallel to the motor. Also with the capacitor you add even more complexity to your circuit. Try it out if you think you know better and prove me wrong, but just selecting a motor that fits your needs is the more simple way and this series of spark erosion is about simplicity.
Very cool
No. Hot enough to melt steel ;-)
It should be possible to run the engraving voltage separate from the motor voltage to give you more adjustment.
One voltage could trigger a transistor or solid state relay to turn the other voltage on and off.
You could experiment with constant current supplies and with constant voltage supplies to get the performance your after.
That's what I mean when I say that I will add an active control to the game. Stay tuned!
Oh. That sounds amazing. I am looking forward to next video. Meanwhile I will try my own experiments
Cool.
Interesting idea using a motor.
you always make interesting things , thank you for the inspiration
how about using a motor to turn a helmet into a speaker? frequency range , response , portability ,stereo possibility , power consumption ,attaching it and removing it , are the questionable parts
Thanks!
Your helmet speaker will work in principle, but don't expect it to deliver high fidelity audio signals. ;-)
i know what im going to be trying next time i break a tap in titanium...
never thought of doing this... lol. yet so simple.
um. the motor has not just resistance but also inductance. the higher power motor will have lower DC resistance, but they also have much lower inductance, generally having a low turn count. do the maths on the numbers you gave, and youll see the resistance and the inductance as it doesnt quite follow ohms law until saturation.
motors have sweet spots, torque variations. the commutator and brush and pole alignment all plays a role... maybe just use a BLDC on one phase?
this is a hard one. is the sparking necessary or not? i think it is but its the nature of that arc... i feel it needs to be a "ringing", much like AC/DC tig welding gives a "cleaning" action... except then you want to wash the arc and resultant byproducts away. iunno. havent played with edm much...
this reminds me of two similar non standard uses... making a servo, and reverb units.
servo. feed, it with a PWM signal, against a spring.
still, i think a standard "bell ringer" type buzzer would work just as well if not better.
Of course, there is more than just ohmic resistance to consider. This is a series on making (sort of) EDM, looking for simple solutions. That "bell ringer" setup has been treated in previous videos. DC motors might be more commonly available than the old school door bells ;-)
In the iteration currently in development I have implemented a microcontroller. Although I do nothing but "replicate" a Wagner Hammer with that setup, yet, a microcontroller offers real time observation and feedback control of what is actually going on. I will do experiments to see whether maintaining the spark as long as possible leads to better results or making and breaking contact at high frequency is to go for.
There is still a lot to be told about a circuit composed of an inductor an a spark gap.
Thanks for sharing your thoughts and don't forget to share the results you get with your setup!
Very entertaining series. I wonder if you can get a higher current through the motor with a reasonably large capacitor on the output to allow the current to discharge on contact and rely on the inductance of the coil to limit it through the motor iteslf.
Well that's what's happening. In fact the computer power supply has an output capacitor. Adding another one won't change that much. You need a power supply that can deliver high current.
So it seems like the issue with these is that the motion of the motor/solonoid is tightly coupled with engraving power. An upgraded version would separate the power for engraving and the power for moving the wire, so in this case you could sense the current through the engraving wire to trigger a different power source for the motor. Then both are driven at exactly the right power
That's what I call "adding active control" to the system, which will be done in one of the coming videos. Stay tuned!
tig welding tungstens and oil cooling oil for oil cooled weleders ,mineral oil.
There is also wear on the tungsten tips. The working principle is different from TIG welding. Making contact with the workpiece quickly wears the pointy tip as shown in a previous video of my EDM series.
@@HomoFaciens I may not have been clear on my meaning , the tungsten should have a prolonged life compared to other metals , and the mineral oil is used in carbon arc erosion i'm sure , I went to college with a guy who needed to get college certificates to work in his dads company doing carbon arc erosion , I watched some stuff about it , we were studying for our electronics technician certificates ,1st year , the oil used is purer than water , mineral water might work well or reverse osmosis water to avoid conduction into the cooling fluid by mineral contamination.
There isn't "the electrode material" nor "the fluid".
As the cooling / flushing fluid must have a low conductivity, oil is in general better than water. But also, messing with oil in your (hobbyist) machinery isn't as comfortable as using deionozed or even tap water. Also discarding the water from time to time is easier than implementing a filter system.
Another yes, tungsten is more resistant to wear in EDM machining because of its high melting point, but there are exceptions from that rule: Heat conduction is another property that reduces wear. Same as with the water or oil decision, brass is cheaper, has a relative low wear and is for those reasons often used.
In another video of that series I had a (very) quick look at different electrode materials:
ua-cam.com/video/rS5600spxEQ/v-deo.html
I will carry out more experiments in the future - stay tuned!
@@HomoFaciens As for a contact conductor you could use a pointed carbon rod,as again for the oil method ,some of the comments by other watchers mentioned an interest opposed to laser etching and i thought i'd add what i knew to work in industrial environments.
Either way, i myself am interested in this method of engraving cast alloy and steel than acid etching,i need to make a cnc controler first though.
Very informative video as always.
All the best.
As with the making and braking contact in my setup, the conductivity of the fluid really doesn't matter that much and tap water works fine. It is simple and cheap and so definitely worth experimenting with.
Thanks for sharing your thoughts!
Ok , so how about using a Tungsten welding electrode for the engraver tip. That would solve the erosion of the engraver while it's engraving the base metal ??
The tip of that electrode will erode same as the tungsten wire, since it is the same material. The electrode tip will become blunt, resulting in wider lines. The pro of the 0.2mm wire is, that the diameter stays constant even if the tip erodes.
Welding electrodes are used in a different way: They are meant to maintain a plasma while with the Wagner hammer there are sparks formed and cut off at a high frequency.
In an earlier video of this series I made use of a sharpened tungsten electrode: ua-cam.com/video/rS5600spxEQ/v-deo.html
Draw power between 3.3 and 12V? Get 8.7V and check how the PSU likes that...
Maybe I will risk one of my old PSUs in a future experiment.
Used 24V on a PC supply before between yellow and I think blue(-12V 0.5A).
Yes, that works in general, but you eventually confuse the maximum current "fuse" of the PSU which might cause damage of your power supply. Spark erosion works with high currents so it is a risk.
Can I ask what software do you use to generate paths? I use inkscape with laser engraving extension and it's kinda clumsy.
And maybe another question. What electrode material can I use? It's just that tungsten wire is kinda hard to get.
I use LibreOffice Draw for the templates, export as svg and then do the conversion into Gcode with a self written Python script.
Use steel, copper, brass or what ever conductive wire you have. I will do some more experiments on material combinations in coming videos. Stay tuned!
its not currency, its current-cy :P
::))
Funny to hear a german practising English.
🎶🎶 You drink coffee I drink beer my dear ... I'm a German man on UA-cam 🎶🎶
As a native English speaker, I understood every word! No issue at all!