STICKMAN'S LETS LEARN CNC THREAD

Stickman393

Well-known member
As my dear sweet wife would say: "At what point do you admit you bought the wrong machine and just throw the whole thing away?" :p

Progress looks great!

In truth, had I just shelled out at the beginning for something like an openbuilds kit, I would have likely spent FAR less on this particular venture...

But...I'm simultaneously always thirsty for knowledge, and an absolute cheapskate. So overall...I'd say the journey has been worth it.

CNC is the sort of thing that is best digested in little bits and pieces. New vocabulary to be learned, new skills, picking up little things like simple Gcode commands, macros, probing...

And there's enough variability in machines that what works for one may not work for another. Say you have a particular problem...like "ah, shit, I need to figure out my zero points here, but my workpiece is non-conductive!".

Well...there's a few different ways to handle something like that. You might buy an aluminum plate that comes with a set of macros that include a g-code command that makes your machine say "NO. no. I ain't doing that shit". Well...then you gotta figure out what the problem is.

It can be a headache, but it's scratching my itch for intellectual stimulation.

As of right now...I had a little hiccup with my X-axis: I couldn't get the damn thing to move when commanding individual 0.1mm travel commands.

I think I've got it narrowed down to a poor setup on my part...the eccentric spacers on my v slot wheel bearings were a bit too tight, and I needed to lube up the lead screw. I took the opportunity to add an extra plate on the backside of the gantry and four extra wheels to share the load.

More creations to come...
 

Stickman393

Well-known member
Time for a quick tech lesson.

My linear power supply is a mean machine. It pumps out AMPS. But...it also...kinda...trips the internal breaker every time I switch it on.

With that huge bank of capacitors, the inrush when I power this thing on is no joke. Which has me concerned...sure, it's annoying having to reset the breaker, but good practice would be to slow that down a bit to avoid undue stress on the components.

So...I'm gonna use a little HVAC trick. This is a delay-on-make timer. Apply voltage across it, and it will trigger an adjustable countdown. At the end of that countdown, a switch between the terminals closes.

IMG_20220214_211030__01_copy_1369x1825.jpg

So...the idea here is pretty simple. When I switch the circuit on, current will travel through a 10 watt 100 ohm resistor. This will limit the inrush current to a large extent...but I don't want the resistor actually in the circuit when im running the power supply.

So, that's where the SPST switch in the diagram below comes into play. That is my delay-on-make timer. I'll set it for something like five seconds so the caps can slowly build a charge. After that point in time, the switch will close, the relay coil will become energized, and the current limiting resistor will be taken out of the circuit.

This is a simplified version, I'm actually going to do the timer control on the 24vac side...just cause that's what I have on hand.

New circuit_copy_576x704.png
 
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fig

Village Idiot
Power to the People! (just not all at once). Similar to the function of a hall-effect sensor?
 

vigilante398

Authorized Vendor
The breaker in my garage was just barely enough to run my CNC, but if someone opened the garage door in the middle of a job the CNC would go down and I would lose whatever I was working on. Eventually I want to get thicker wire run so I can swap for a beefier breaker, but until then I hooked the CNC up to a UPS backup. It isn't enough to run the machine for a long time, but it's enough to hold it up in case of the line going down so I don't lose my work.

When I run my curing oven the lights still flicker, so maybe I should get that checked out by a professional.
 

vigilante398

Authorized Vendor
What uv printer do you have if you don’t mind me asking? If it’s over $1000 don’t worry about it🤣
Alas with the printer, shipping, and a set of inks it was about $3,000. So if you have a business entity set up for pedal building it's tax deductible, but even then I'm not sure I would recommend it :p Tayda does great work for a good price, and UV printers need constant maintenance to keep them running nicely. If you're building a lot of pedals for paying customers it eventually pays for itself, but it takes A LOT of paying customers to make it worth it over using a service like Tayda.

I think I did the math like 8 months after buying it, and if I had just used Tayda's print service I still would have saved money even after doing printing myself for 8 months.
 

Paradox916

Well-known member
I’m just a hobbyist that likes nice stuff at best… I have sold a few pedals but I only do so just to keep me in the hobby as my full time job now is a little girl with some extra needs… soIm going to keep with the decals for now and maybe dip my toe into a print service later. I was just curious.
 

vigilante398

Authorized Vendor
I did decals for years before I got my first CNC and started engraving artwork, then from there I actually bought a cheap (~$400) laser engraver, both of which are also options for professional-quality DIY artwork. Between the two I would say CNC is easier to get started and takes less maintenance (although @Stickman393 is starting to prove me wrong :p )
 

Stickman393

Well-known member
PShots fired!

Yeah, it's the mechanic in me. Plus I'm averse to dropping over $500 on anything at a time, but seem to be super willing to drop 2kish over a period of half a year for something that is significantly inferior to a machine.

But...can't put a price in knowledge. Learned a lot by fucking around with a cheapie. And more likely than not I'll end up rebuilding the base and converting the original to a laser engraver.

Power to the People! (just not all at once). Similar to the function of a hall-effect sensor?

Honestly, I don't quite know how it works on the inside. I wouldn't be surprised to open it up and see a 555 and a FET in there.

These little modules are super common in large commercial units that lack microprocessor controls. Like, for instance, in a makeup air unit, which conditions outside air and pumps that air into a building, typically in buildings like kitchens or labs that lose a lot of air through exhaust fan use. The air "makes up" for the air lost to exhaust and keeps the walls and windows from imploding on themselves.

In this situation, someone my want to use a single "Start/Stop" digital command to start a fan AND open a set of damper blades. Maybe it's a simple controls setup, where that start/stop command is coming from a current relay that is wrapped around a leg of a three phase exhaust fan. Or from a relay output on a VFD.

WELL...you don't want that fan operating until those damper blades are open. But with only a single command available, you need to find a way to stage the damper blades to open FIRST, and then for the fan to come online.

Truthfully, the better option in this case would be to use a limit switch on the damper actuator in series with the coil of the fan relay, but one of these could do the trick too. Put it in series with the fan relay coil, set the timer to, say, 90 seconds for a 90-second-stroke actuator, and the fan will energize roughly 90 seconds after the unit gets a "start" command.

I <3 relays.

The breaker in my garage was just barely enough to run my CNC, but if someone opened the garage door in the middle of a job the CNC would go down and I would lose whatever I was working on. Eventually I want to get thicker wire run so I can swap for a beefier breaker, but until then I hooked the CNC up to a UPS backup. It isn't enough to run the machine for a long time, but it's enough to hold it up in case of the line going down so I don't lose my work.

When I run my curing oven the lights still flicker, so maybe I should get that checked out by a professional.

Whatcha running there, a 15 amp breaker?

That would be pretty typical of older residential wiring. Pretty common to see 14awg Romex going to a line of 15amp breakers. I've got the same sort of setup in my house.

12awg Romex can be run up to 20 amps if you don't need to derate it. I ran a little extra circuit in my garage with 12awg Romex for a similar reason.

Still though, whatcha running, a three phase spindle + VFD? Might even be fixed with a newer garage door opener, especially if it's happening like THE MOMENT the garage door starts to open.

Locked rotor amps can easily be 5-10x rated load amps. Some newer models feature a soft start that helps mitigate that current spike that is characteristic of motors that tend to start when voltage is applied across the line.

Then again, I don't know how much electricians cost. Outside of the commercial sphere, at least. More than I do, that's for sure *grumbles about the plumbers in my union that voted for a pay raise last year that wont keep up with inflation*.
 
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vigilante398

Authorized Vendor
Whatcha running there, a 15 amp breaker?

That would be pretty typical of older residential wiring. Pretty common to see 14awg Romex going to a line of 15amp breakers. I've got the same sort of setup in my house.

12awg Romex can be run up to 20 amps if you don't need to derate it. I ran a little extra circuit in my garage with 12awg Romex for a similar reason.

Still though, whatcha running, a three phase spindle + VFD? Might even be fixed with a newer garage door opener, especially if it's happening like THE MOMENT the garage door starts to open.
It's actually a 10A breaker. Smallest one anywhere else on the house is a 15A, for some reason the garage of all things got a 10A. The house was built in 1997 though, can't really blame age. I'm wondering if the wire in there can already handle more and they just put a 10A as a joke.

Garage door opener is brand new, I installed it when we moved in. It is a 3-phase 800W spindle with a VFD though. It's on the beefy side of things.

EDIT: looks like I lied, garage is a 15A breaker, most of the others in the house are 20A.
 
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Stickman393

Well-known member
Hmmm.

I mean, VFDs tend to have very good efficiency ratings...though all of my experience with VFDs has been in three phase to three phase applications. But that spindle shouldn't be pulling much more than 800 watts at full load...I can't imagine that would be a post-power factor rating.

What kind of steppers are ya using? A popular NEMA 23 is rated at 2.8 peak...three of those at 24v running balls out would pass about 200 watts.

Plus...if you're running a desktop computer to drive the CNC, that could be an extra 200 watts.

A 15 amp breaker is good for about 1800 watts, so that leaves about 600W for the garage door opener.

Plus lighting, etc. That's about 5 amps of headroom...I could easily see a garage door opener spiking right past that with it's rotor locked. I suppose I should have emphasized the "soft start" part of that...new doesn't necessarily mean that the motor won't spike initially.

97 is pretty new, easily in the time when 12awg would be the norm. So...the mystery of the 15 amp breaker could come down to a few different things:

1) the electrical contractor used 12 in the house but 14 for the garage due to permissive local codes and penny pinching. Unbelievable if it's a one-off house, but I could see if it was built in part of a new development where they were building multiples.

2) it's actually 12 gauge, but they had to use a 15 amp breaker because the inspector slapped 'em for installation practices that required derating that one circuit.

3) It's 12 gauge, but a 15 was all someone had on hand either during the install or a repair.

Could even be due to their GFCI selection in the garage...maybe they used gfci outlets that were only rated for 15 amps cause someone ordered wrong. Round here GFCIs are required in garages; it's considered a "non-dry" area like a kitchen or bathroom. Could be a GFCI breaker, too...

Could even be beneficial to look at the breaker *type*. Seeing as how much of the garage consists of inductive loads, if that 15 amp breaker isn't an HACR type, that alone could solve the problem. HACR breakers are kinda like a slo-blo fuse...typically used for Heating, Air Conditioning, and Refrigeration circuits: they're good at handling transient spikes in current without tripping. We got LOTS of those in HVAC.

Eh...I apologize if this is all just unsolicited advice. My brain instantly jumps to "OOOOH! LETS FIGURE THIS OUT!" when presented with building construction-related issues.
 

fig

Village Idiot
Eh...I apologize if this is all just unsolicited advice. My brain instantly jumps to "OOOOH! LETS FIGURE THIS OUT!" when presented with building construction-related issues.
Excellent! The nano-bot treatment was a success. We can now re-program workers to whatever vocation suits us!
 

vigilante398

Authorized Vendor
Hmmm.

I mean, VFDs tend to have very good efficiency ratings...though all of my experience with VFDs has been in three phase to three phase applications. But that spindle shouldn't be pulling much more than 800 watts at full load...I can't imagine that would be a post-power factor rating.

What kind of steppers are ya using? A popular NEMA 23 is rated at 2.8 peak...three of those at 24v running balls out would pass about 200 watts.

Plus...if you're running a desktop computer to drive the CNC, that could be an extra 200 watts.

A 15 amp breaker is good for about 1800 watts, so that leaves about 600W for the garage door opener.

Plus lighting, etc. That's about 5 amps of headroom...I could easily see a garage door opener spiking right past that with it's rotor locked. I suppose I should have emphasized the "soft start" part of that...new doesn't necessarily mean that the motor won't spike initially.

97 is pretty new, easily in the time when 12awg would be the norm. So...the mystery of the 15 amp breaker could come down to a few different things:

1) the electrical contractor used 12 in the house but 14 for the garage due to permissive local codes and penny pinching. Unbelievable if it's a one-off house, but I could see if it was built in part of a new development where they were building multiples.

2) it's actually 12 gauge, but they had to use a 15 amp breaker because the inspector slapped 'em for installation practices that required derating that one circuit.

3) It's 12 gauge, but a 15 was all someone had on hand either during the install or a repair.

Could even be due to their GFCI selection in the garage...maybe they used gfci outlets that were only rated for 15 amps cause someone ordered wrong. Round here GFCIs are required in garages; it's considered a "non-dry" area like a kitchen or bathroom. Could be a GFCI breaker, too...

Could even be beneficial to look at the breaker *type*. Seeing as how much of the garage consists of inductive loads, if that 15 amp breaker isn't an HACR type, that alone could solve the problem. HACR breakers are kinda like a slo-blo fuse...typically used for Heating, Air Conditioning, and Refrigeration circuits: they're good at handling transient spikes in current without tripping. We got LOTS of those in HVAC.

Eh...I apologize if this is all just unsolicited advice. My brain instantly jumps to "OOOOH! LETS FIGURE THIS OUT!" when presented with building construction-related issues.
Lol, no worries I appreciate the advice. The garage is on the main floor and the electrical panel is in the basement, all wiring goes through metal conduit, and the garage walls are finished so rewiring means cutting through drywall and hacking into metal conduit, otherwise it would have been the first thing I did when we moved in.

The VFD is going from 2-phase to 3-phase so it's going to lose some efficiency, but admittedly I've never actually measured how much it pulls. They are NEMA 23 motors, but the labels say 4.2A, they're the 114mm model. I run them a lot slower than than they're capable of going though, running them balls to the wall the spindle can't keep up.

I had a plug-in power meter at our old house that I used to help solve things like this, and now I have no idea where it is, I'll have to find that and take some measurements. The UPS was an easy workaround since I already had it lying around, and having a UPS on machines that regularly do multiple-hour jobs and the computer that runs them (it's a mini-desktop, so more power hungry than a laptop but less than a gaming PC) is a pretty good idea.
 

Stickman393

Well-known member
I gotcha! You may be able to tell if the breaker is "HACR type" by looking at the face of the breaker in the panel. I know like...99% of residential multi pole breakers are...but I don't actually know about single pole breakers.

All in conduit, huh? Hmmmm. Typically THHN is rated for a bit higher current at 90⁰ than equivalent Romex...Romex isn't really allowed in conduit for anything over very short distances. Typically you can use a 14 gauge instead of 12 with a 20 amp breaker, before derating. Though that alone could be why that one is current limited...maybe they stuffed too many wires into too small of a conduit. Lots of factors go into derating...lots more than I have knowledge of. I'm just an HVAC guy...my electrical knowledge as far as buildings go is better than the average joe, but nowhere near a that of a licensed electrician.

But I'll talk your ear off about hear transfer, itellyouwhat. Yup...got lots of friends.

Re: @fig I was able to open this thing up and get a gutshot!

IMG_20220216_145558_copy_1550x2068.jpg

Ahhhhhh shit. Even mars goops their circuits.
 

vigilante398

Authorized Vendor
I gotcha! You may be able to tell if the breaker is "HACR type" by looking at the face of the breaker in the panel. I know like...99% of residential multi pole breakers are...but I don't actually know about single pole breakers.

All in conduit, huh? Hmmmm. Typically THHN is rated for a bit higher current at 90⁰ than equivalent Romex...Romex isn't really allowed in conduit for anything over very short distances. Typically you can use a 14 gauge instead of 12 with a 20 amp breaker, before derating. Though that alone could be why that one is current limited...maybe they stuffed too many wires into too small of a conduit. Lots of factors go into derating...lots more than I have knowledge of. I'm just an HVAC guy...my electrical knowledge as far as buildings go is better than the average joe, but nowhere near a that of a licensed electrician.

But I'll talk your ear off about hear transfer, itellyouwhat. Yup...got lots of friends.

Re: @fig I was able to open this thing up and get a gutshot!

View attachment 23148

Ahhhhhh shit. Even mars goops their circuits.
I had one of those a couple years ago that I had opened up and there was no goop, I may even have pictures on my old phone. I'm definitely not an HVAC guy, but when I tried to hook my nest up to a swamp cooler (when I lived in the desert) everyone told me it was impossible, so I had to prove everyone wrong. Basically just needed to turn on the water pump and let it run for 45 -60 seconds before turning on the fan, thus the timer. Worked a treat in my friend's older AC-controlled system, but all my thermostat controls were 3.3VDC logic, so I designed a NE555-based timer circuit to do the same thing at the 3.3VDC level instead of the 120VAC level.

And thus began and ended my foray into hacking HVAC systems. I didn't want to do it, but Nest told me it was impossible, and the swamp cooler manufacturer told me it was impossible. You don't tell an engineer something is impossible.

I'll take a look at the breakers sometime and keep you posted. Sorry for the temporary derail :p
 

vigilante398

Authorized Vendor
Dude. I've used nothing but flat end mills or v-bits since I got my CNC, but I got my first ball nose bits over the weekend, and man I wish I had checked these out sooner. Absolutely fabulous for a nice popping "3D look".
 
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