Hello Guest it is November 13, 2019, 12:38:55 AM

Author Topic: Impact engraving plugin  (Read 259095 times)

0 Members and 1 Guest are viewing this topic.

Offline Dan13

*
  •  1,244 1,244
    • View Profile
    • DY Engineering
Re: Impact engraving plugin
« Reply #370 on: June 09, 2017, 02:46:00 PM »
300Hz!!!!!!!???? WOW! So your mechanics using the magnets is MUCH superior to mine using a spring. Still interesting why does the L298 gives me a much lower frequency than the other driver. By the way, a nice feature of the other driver is that I can limit the current and set an idle current.

Why in your design you move the solenoid instead of the magnets? You need then fatigue resistant wire so that it doesn't break. It could be very helpful if you could post a simple sketch of your impact head mechanics. You have described it in this thread previously, but afraid I was picturing it differently than what I am understanding now.

So you have a board converting PWM to frequency?

Dan
« Last Edit: June 09, 2017, 02:48:13 PM by Dan13 »
Re: Impact engraving plugin
« Reply #371 on: June 09, 2017, 04:58:06 PM »
Hoje much does your Lever moves?
Mine About 1,2 to 2 mm.It does not even stress the wire. As Said i control Just the voltage with a dc-dc downloader I can input 48 vcc but let only 5- 12 go to lm298 , and 2A .
The neodymiun will drastic reduce it's eficiency if you get it too hot , so if you put it on aluminium an fixed it gets a natural dissipation, in my recent machines I even put a cooler.
« Last Edit: June 09, 2017, 05:02:42 PM by Jan Mozol »
Re: Impact engraving plugin
« Reply #372 on: June 09, 2017, 05:12:49 PM »
And when you have a S0 in my board you just have 0 volts, 0 amperes in the coil, the spring and the magnets just pull it up , you dont need iddle , you are using PWM , 0 volts means zero warming, zero iddle .
When you have S1000 you have full voltage in 'x' milliseconds derived from HZ , so you can have up to 5 small impacts in each pixel , so, if I apply 10 vcc in my lm-298 it will cause the  coil to impact 5 times the pixel at 10 vcc , this 10 vcc comes from a dc-dc downloader , if i put 5 vcc it will be the maximun , but if I am doing basalt , i will input even 15 vcc.
My best results in granite are with 10 vcc  , and 1 karat diamonds , if you look carefully you will see that i dis a screw on the body of the diamond ( 6 mm thread) and I have two nuts in the point of the lever, so I can adjust the height of the diamond refering to the granite , this is very important, a long course will get the job slow , I put it to 1,2 to 2 mm according to material.
Re: Impact engraving plugin
« Reply #373 on: June 09, 2017, 05:18:20 PM »
New development...colored impact with alcaline pigment that just gets inside engraving.
I really liked it

Offline Dan13

*
  •  1,244 1,244
    • View Profile
    • DY Engineering
Re: Impact engraving plugin
« Reply #374 on: June 10, 2017, 07:05:13 AM »
The coloured engraving came out real nice.

The stroke of my plunger is around 0.6-0.8mm

So you have a fixed frequency and you only control the impact force by varying the voltage?

Where did you get your coils from? Or did you wind them yourself? I used a 12V solenoid (around 25 ohm -> 0.5A) which I made a new housing an plunger for where I can mount the tips. The spring force is around 500g.

My main concern when making the new plunger and housing was to minimize the wobble of the plunger inside the sleeve, because I was afraid any wobble could play a significant role in ruining high resolution super fine engravings. So my plunger is not too lose and hence has some minor resistance moving.

Dan
Re: Impact engraving plugin
« Reply #375 on: June 10, 2017, 12:38:33 PM »
The slope of the diamond I calculated so that at impact, which I call impact point, it would be at 90 degrees My coils have 40 ohms, and are calculated to 24 vcc with impact force of 1 kgf
My lever is fixed by two bearings, you feel no resistance, it is super free and it does not move sideways.
As for frequency, it is regulated by hue and pwm, I will try to explain:
If you regulate the voltage input on the lm298 in 10 volts, it will give pulses by the tone at the output of the breakboard, and at the same time it will divide the 10 vcc by the voltage input, so it is, it will impact with more power where She finds the color darker and for less where she finds it lighter.
If I increase the input voltage of the lm298 it will continue at the same pitch frequency, but with more force relative to the voltage input.
Although I'd rather do with 0 and 1000, using my 1 bit bitmap images.
I'm preparing 5 impact heads for my machines, and I'm going to sell some.
I'm also adapting to GBRL, and getting excellent results, although the control software is much simpler than Mach3 and less user friendly, I've already compiled a g-code sender in Visual C #.

Offline Dan13

*
  •  1,244 1,244
    • View Profile
    • DY Engineering
Re: Impact engraving plugin
« Reply #376 on: June 10, 2017, 03:58:41 PM »
Hi Jan,

OK. I think I now see the main mechanical difference between my construction and yours. You have a lever, while I have a plunger. Along the whole way you've been talking about your lever, but somehow I was ignoring it.

So I think if made as a lever supported by ball bearings, a spring could work just as well as magnets.

Thanks,
Dan
Re: Impact engraving plugin
« Reply #377 on: June 10, 2017, 05:40:11 PM »
My First design were Spring , but was difficult to adjust and would Warm too much .Magnets do not weaken do not Break.

Offline Dan13

*
  •  1,244 1,244
    • View Profile
    • DY Engineering
Re: Impact engraving plugin
« Reply #378 on: June 11, 2017, 12:41:36 AM »
Thanks Jan. Will construct a new one and update how it worked out.

Dan

Offline Dan13

*
  •  1,244 1,244
    • View Profile
    • DY Engineering
Re: Impact engraving plugin
« Reply #379 on: July 03, 2017, 10:08:45 AM »
Hi Jan,

Built a new head with a lever and magnets, but was not able to drive it fast. Only then I did away with the 24VDC commercial solenoid (around 130 ohm) and wound my own solenoid having 2 ohm. With this one I can easily do 50 and 100 HZ. But to get reliable 100HZ at full lever amplitude (around 1mm), I have to use 70% duty cycle.

Anyway, the L298 can't limit the current. I am using a 12 VDC 2A power supply, so in a minute it gets VERY hot! As well as the solenoid. It appears that a fan helps to some extent. Do you also encounter these heat dissipation issues?

Dan