Mostly 3D Printed CNC Foam cutter
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17 Jul 2024 15:15 #305498
by tommylight
Replied by tommylight on topic Mostly 3D Printed CNC Foam cutter
I do not use it, a client does, and he is one of those "why do something simple when you can complicate it" so he uses AutoCAD to make the drawings, then imports into Inkscape and exports as gcode from it.
For the 5 axis stuff he uses something else and despite telling me a dozen times, i forgot what, sorry.
For the 5 axis stuff he uses something else and despite telling me a dozen times, i forgot what, sorry.
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18 Jul 2024 00:35 #305549
by my1987toyota
Replied by my1987toyota on topic Mostly 3D Printed CNC Foam cutter
ahh don't sweat it . I have been a bit busy today doing research for the LCNC change over from GRBL.
PCW gave me a few Idea's to try out and I already have a basic profile on a 9020 optiplex. The
big thing will be setting the 7i96 to handle temp control of the hot wire.
PCW gave me a few Idea's to try out and I already have a basic profile on a 9020 optiplex. The
big thing will be setting the 7i96 to handle temp control of the hot wire.
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18 Jul 2024 10:25 #305564
by tommylight
Replied by tommylight on topic Mostly 3D Printed CNC Foam cutter
Use a MOSFET to control the wire current and subsequently the temperature, controlled as a spindle so you can adjust it during work.
MOSFET's usually require 10-15V to open fully but there are logic level ones that need about 4V on the gate to fully open, so depending on that you can use the Mesa outputs, there are some caviats there but we'll deal with that when we get there.
MOSFET's usually require 10-15V to open fully but there are logic level ones that need about 4V on the gate to fully open, so depending on that you can use the Mesa outputs, there are some caviats there but we'll deal with that when we get there.
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18 Jul 2024 10:37 #305567
by tommylight
Replied by tommylight on topic Mostly 3D Printed CNC Foam cutter
Or, it just occurred to me, i have used those cheap arduino BTS7690 or whatever the numbers are, to control a heated bed on a 3d printer, worked perfectly and stayed cool at 12A of current. Think of it as 2 of high side and 2 of low side FET's, and they can be controlled from low level Mesa pins so can use hardware PWM at high frequencies.
Also makes wiring much easier and are very cheap.
Also makes wiring much easier and are very cheap.
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18 Jul 2024 20:38 #305595
by my1987toyota
Replied by my1987toyota on topic Mostly 3D Printed CNC Foam cutter
When I get a chance I will check into that. For now though I already have this SSR .
www.amazon.com/dp/B079BGGVYX?psc=1&ref=p...dt_b_product_details
www.amazon.com/dp/B079BGGVYX?psc=1&ref=p...dt_b_product_details
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23 Jul 2024 21:57 #305931
by my1987toyota
Replied by my1987toyota on topic Mostly 3D Printed CNC Foam cutter
well so much for that solid state relay. the one I got only seems to work as an on/off switch and doesn't
have any in between. We will see if the below will work better. At least they are designed from the start
for PWM.
www.amazon.com/gp/product/B07C7RQ4C6/ref...00_s00?ie=UTF8&psc=1
have any in between. We will see if the below will work better. At least they are designed from the start
for PWM.
www.amazon.com/gp/product/B07C7RQ4C6/ref...00_s00?ie=UTF8&psc=1
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24 Jul 2024 14:09 #305960
by spumco
Maybe I'm misinterpreting your post, but all relays (SSR and otherwise) are on/off. They aren't analog; there's no 'in-between' state of a relay (hopefully).
And, depending on the switching speed limit, all SSR's can be used with PWM control. SSR's are (generally) fast enough that a PWM signal can turn them on/off quickly so the end result appears as an analog voltage output to the consuming component.
Like a heater (3d printer hot-end, bed, or a hotwire cutter).
If the SSR you first tried doesn't work with PWM, it may be that the PWM output/control frequency is higher than the maximum switching speed of that particular SSR.
Or have I completely missed the point of what you were trying to say?
Replied by spumco on topic Mostly 3D Printed CNC Foam cutter
well so much for that solid state relay. the one I got only seems to work as an on/off switch and doesn't
have any in between. We will see if the below will work better. At least they are designed from the start
for PWM.
www.amazon.com/gp/product/B07C7RQ4C6/ref...00_s00?ie=UTF8&psc=1
Maybe I'm misinterpreting your post, but all relays (SSR and otherwise) are on/off. They aren't analog; there's no 'in-between' state of a relay (hopefully).
And, depending on the switching speed limit, all SSR's can be used with PWM control. SSR's are (generally) fast enough that a PWM signal can turn them on/off quickly so the end result appears as an analog voltage output to the consuming component.
Like a heater (3d printer hot-end, bed, or a hotwire cutter).
If the SSR you first tried doesn't work with PWM, it may be that the PWM output/control frequency is higher than the maximum switching speed of that particular SSR.
Or have I completely missed the point of what you were trying to say?
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24 Jul 2024 15:11 #305965
by tommylight
Replied by tommylight on topic Mostly 3D Printed CNC Foam cutter
Two types of SSR:
1. AC type, turns on normally, does not turn off at all UNTIL the outputs voltage drops to 0, can do PWM at very low rates, usually limited by the mains frequency, uses TRIAK's or THyristors
2. DC type, can be switched on and off normally, uses MOS-FET's, can do pretty high frequency PWM.
As for the linked SSR by Toyota, simple MOSFET's that may or may not have issues with proper gate driving, does not state what exact MOSFET they use (they call it tube) so no way of knowing if the used type is TTL level ones.
MOSFET - can be only on or off, except when actually required to heat like when used in DC load testers, TTL level ones require ~4V on the gate to open fully, all others ~15V, have capacitance on the gate so will not turn off without a resistor tied to gate and source pins, or other means of getting rid of the capacitance, best driven by push-pull drives, very low resistance when fully on
TRANSISTORS - can be controlled linearly (depends) and will proportionally allow current to flow between Emitter and Collector depending on the Base current/voltage, always heat at higher currents as they always have some drop in voltage.
Not easy to shrink all the info, sorry.
1. AC type, turns on normally, does not turn off at all UNTIL the outputs voltage drops to 0, can do PWM at very low rates, usually limited by the mains frequency, uses TRIAK's or THyristors
2. DC type, can be switched on and off normally, uses MOS-FET's, can do pretty high frequency PWM.
As for the linked SSR by Toyota, simple MOSFET's that may or may not have issues with proper gate driving, does not state what exact MOSFET they use (they call it tube) so no way of knowing if the used type is TTL level ones.
MOSFET - can be only on or off, except when actually required to heat like when used in DC load testers, TTL level ones require ~4V on the gate to open fully, all others ~15V, have capacitance on the gate so will not turn off without a resistor tied to gate and source pins, or other means of getting rid of the capacitance, best driven by push-pull drives, very low resistance when fully on
TRANSISTORS - can be controlled linearly (depends) and will proportionally allow current to flow between Emitter and Collector depending on the Base current/voltage, always heat at higher currents as they always have some drop in voltage.
Not easy to shrink all the info, sorry.
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24 Jul 2024 16:20 #305968
by my1987toyota
Replied by my1987toyota on topic Mostly 3D Printed CNC Foam cutter
The SSR I was using was a DC to DC solid state relay.And I agree the problem I had was probably due to the pwm switching frequency
being too high as it went from nothing to holy crap my wire is glowing with the control only commanding a change between
5 to 10 percent. On my stand alone Hot wire power supply which uses a PWM brushed motor controller and gives me plenty
of linearity. Both are using 24VDC power. The mosfet I ordered is set from the start to drive and control a heater. Bed, Hot
wire, doesn't matter. They're both resistance heaters. Right now the control on the foam cutter is using GRBL. I am still
struggling to get a working PWM signal coming out of my 7196 to drive a circuit to control the hot wire. And since I need
my foam cutter operational for a demonstration for some people I know at the flying club I needed something with a
high probability of success to work. For now the SSR isn't it. Fortunately I still have my stand alone power supply and
if I must I will use that for the demonstration. I just don't have a whole lot of faith in the free standing mosfet on the RAMPS
1.4 board D8 position. I could be wrong , but having a mosfet burn up mid way through a demonstration don't look good.
LOL.
being too high as it went from nothing to holy crap my wire is glowing with the control only commanding a change between
5 to 10 percent. On my stand alone Hot wire power supply which uses a PWM brushed motor controller and gives me plenty
of linearity. Both are using 24VDC power. The mosfet I ordered is set from the start to drive and control a heater. Bed, Hot
wire, doesn't matter. They're both resistance heaters. Right now the control on the foam cutter is using GRBL. I am still
struggling to get a working PWM signal coming out of my 7196 to drive a circuit to control the hot wire. And since I need
my foam cutter operational for a demonstration for some people I know at the flying club I needed something with a
high probability of success to work. For now the SSR isn't it. Fortunately I still have my stand alone power supply and
if I must I will use that for the demonstration. I just don't have a whole lot of faith in the free standing mosfet on the RAMPS
1.4 board D8 position. I could be wrong , but having a mosfet burn up mid way through a demonstration don't look good.
LOL.
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24 Jul 2024 19:04 - 24 Jul 2024 19:05 #305972
by tommylight
Replied by tommylight on topic Mostly 3D Printed CNC Foam cutter
Use a BTS7690 or whatever numbers, very cheap, has no slow optocouplers to mess the signal, as there is no need for isalation from the same power supply.
And each can controll 2 heaters independently (well it can do 4 but ... ), can handle over 30A i think on each IC.
Edit:
Oooops, i mentioned this before on this topic, sorry.
And each can controll 2 heaters independently (well it can do 4 but ... ), can handle over 30A i think on each IC.
Edit:
Oooops, i mentioned this before on this topic, sorry.
Last edit: 24 Jul 2024 19:05 by tommylight. Reason: see above
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