[Miata2k]

I did not want to install another 12V power supply and cut the strips into 10 pieces. Wired in series with a small bridge rectifier they are now powered directly from 120 V

Jerry,

I really like the light you added to the spindle, I may have to steal your idea for my machines.

I'm not sure of your background but I'd like to point out something that may be informative or not. Taking the 120 v AC though a bridge rectifier gives you an average voltage around 100 volts DC, but the peak is almost 170v DC.

From a quick Google search:
Four-Diode Full-Wave Bridge Rectifier

If you decide the lights are just just too bright you can switch to just a half wave rectifier and a capacitor to clean up the output voltage. I wouldn't recommenced adding a cap to your current setup because with the wrong size cap it could be possible to bring the DC voltage up high enough to destroy the LED's.

Youtube Video Here This is cutting the blanks for y and z axis hand wheels from 1.75" black walnut for 2-sided 3D machining.

The machine looks like it working very well. I like seeing the materials you are using on your projects, first the bamboo plywood and now the black walnut. The only products I've ever used for projects come from my local mega lumber yard, MDF and Plywood.


-C

[JerryBurks]

........I'm not sure of your background but I'd like to point out something that may be informative or not. Taking the 120 v AC though a bridge rectifier gives you an average voltage around 100 volts DC, but the peak is almost 170v DC.....

Thanks for the hint. Now I happen to be an EE and I am pretty sure this application meets the specs of the LED.

You are right that the AC peak voltage is 120V times square root of 2, that means about 170V. But the RMS value (root mean square) is still 120V when just rectified and not filtered with a capacitor. If you would use a large capacitor that stores energy while the AC is going through zero, then the resulting DC would indeed be 170V which is why I did not add a capacitor.

The voltage is anyway not necessarily the limiting factor for these LED strips. An LED itself is pretty much a constant voltage device, operating at approx. 3.2 Volts per LED. There are 3 such LED in series for every 12V section and the remaining 2.4 V have to be dropped by a current limiting resistor on the strip. While the rectified pulsed operation temporarily exceeds the nominal current, the RMS average is still in spec. You could use a single diode to rectify instead of the bridge rectifier but then the RMS voltage is only 60V and you need only five 12-strips. That should still work O.K. but you may see an ugly flicker since the frequency is only 60HZ with long off-periods instead of 120Hz with the bridge rectifier.

[JerryBurks]

...........The machine looks like it working very well. I like seeing the materials you are using on your projects, first the bamboo plywood and now the black walnut. The only products I've ever used for projects come from my local mega lumber yard, MDF and Plywood.....

I am quite happy with the machine so far. Like always there are certain things that one would do differently with 20/20 hindsight and once it is complete I will probably post a "lessons learned".

The choice of Bamboo for the machine was deliberate and driven by design goals. The choice of Black Walnut for the hand wheels was rather driven by what I had on hand in that thickness. Well, and it looks pretty when finished. Otherwise it could have been any hardwood or even good plywood. Actually, the hand wheels will have folding crank handles out of some scrap pieces of Myrtlewood

[kinghong1970]

pc modding folks uses LED strips that connect to the molex of your computer as well.
perhaps that makes it simpler?

Strip Lights : Performance-PCs.com, ... sleeve it and they will come

[JerryBurks]

pc modding folks uses LED strips that connect to the molex of your computer as well.
perhaps that makes it simpler?

Well, actually the way I hooked it up does not get any simpler. The led strips I used are similar to the ones in your link. They all can be cut into segments with 3 LED each (or multiples of 3).

If I would have used them as-is with a 12V power supply it would have required one with at least 2 amps. But wiring in series with a $2 rectifier is less expensive and just a cleaner install.

However.....(disclaimer here).....since this means wiring AC mains voltage one would have to be sure to know what they are doing. It is not easy to see in the picture but I encapsulated the recess with the LED strips with a pour of epoxy so that no wires can be touched and the whole thing is insulated from the wood. The epoxy cast also helps to dissipate the heat from the LEDs and the current limiting resistors in the strips. They do get pretty warm.

[RomanLini]

Nice work on the LEDs and dust boot Jerry.

Re running the LEDs directly from 120v after the rectifier, I would still consider a resistor and cap between the mains and the LEDs to tame the mains spikes, which are known for killing LEDs. With the right resistor and cap choice you can still run at the average 120v. I'm just thinking of how much work it would be to change LEDs once they are epoxied in, especially since the failure mode is usually opencircuit so one dead LED will take out a whole series string.

[JerryBurks]

......... I would still consider a resistor and cap between the mains and the LEDs to tame the mains spikes, which are known for killing LEDs. .........

I believe I qualify as a "reckless designer"....but I did check the Cree web site. They have an interesting paper about pulsed operation of power LED and they state that unfiltered rectified AC is a common and proven way of running LED lighting. Problems are sometimes encountered when using very high current low-duty-cycle pulses for multiplexed applications.

The LED strips do have current limiting resistors already built in and due to the rectification, all mains transients should only show up in the "pass" polarity of the LEDs. So a small cap may help suck them up but I am not sure if really necessary.

The encapsulated LED plate is obviously a disposable item. But I hope with a rated life of 50,000 hours it will exceed the usable life of the machine.

[RomanLini]

It will probably work for lots of happy years Jerry! I'm a bit sensitive with mains connected stuff being from a 240v AC mains country (which often sees 255v mains!) and the "voltage squared" fact that our spikes are 4x more destructive than 120v mains.

It's not unusual here to see 2kV high energy spikes on the mains here happening all day long when fridges turn on/off etc.

Anyway I'm a bit jealous of your LED setup, I'd love to have that much light on my CNC machine, I have to reach for the torch at times...

[JerryBurks]

It will probably work for lots of happy years Jerry! I'm a bit sensitive with mains connected stuff being from a 240v AC mains country (which often sees 255v mains!) and the "voltage squared" fact that our spikes are 4x more destructive than 120v mains.

It's not unusual here to see 2kV high energy spikes on the mains here happening all day long when fridges turn on/off etc.

I hear you...and the voltage here in SoCal also fluctuates up to 130V sometimes.

Anyway I'm a bit jealous of your LED setup, I'd love to have that much light on my CNC machine, I have to reach for the torch at times...

Was not that much work: Designing and cutting the plate one evening. Wiring and potting another one. And the LED strips from eBay were something like total $25 for two 1 meter strips with 5050 size SMT LED.

[RomanLini]

Thanks for the tip on the LEDs. There's not much room on my machine for lights, but I'm always thinking of making a big dust box to put the machine in and if/when I get around to it it would be great paint it white inside and put a heap of LEDs on the walls and under the lid.

I think small lights coming from all directions is great lighting compared to one or two strong light sources with all the shadows etc, especially looking at machined parts with slots and details cut in them.

[JerryBurks]

......... I'm always thinking of making a big dust box to put the machine in and if/when I get around to it it would be great paint it white inside and put a heap of LEDs on the walls and under the lid....

I had such a dust box with plexiglass windows on my old machine, although not with LED light but 2 slim fluorescent light tubes. That worked pretty good, also cut down the noise noticeably.

I did not build such a box for my new machine because it would be just humongous and limit free access from all sides. I would prefer a small separate noise-insulated room for the machine but, the required bigger house would definitely exceed my CNC hobby budget

[zool]

Jerry stated: "I would prefer a small separate noise-insulated room for the machine but, the required bigger house would definitely exceed my CNC hobby budget"


Jerry Jerry. Once again you have your priorities wrong!

Sell the house. Buy a small industrial building [say 5,000 square feet] with 24-foot clear ceiling heights and install an apartment in the area above the first floor.

This way you can have lots of room for all your toys and a nice living space too. Neighbors leave around 5PM, so you won't have to be bothered by or about them.


The wife factor.

I have been advancing this idea to my wife for a couple years. At first she was skeptical, but has come around in the last six-months.

She dislikes [BIG understatement!] our neighbors [we live in a condominium]. She likes astronomy, and I have taken her to the small industrial park my studio is in and she likes how dark it is there at night. She also figured out she would not have to worry about me being in my studio alone [I rent a space in a multi-tenant industrial building].

Hey, its worth a shot!!

[louieatienza]

Jerry stated: "I would prefer a small separate noise-insulated room for the machine but, the required bigger house would definitely exceed my CNC hobby budget"


Jerry Jerry. Once again you have your priorities wrong!

Sell the house. Buy a small industrial building [say 5,000 square feet] with 24-foot clear ceiling heights and install an apartment in the area above the first floor.

This way you can have lots of room for all your toys and a nice living space too. Neighbors leave around 5PM, so you won't have to be bothered by or about them.


The wife factor.

I have been advancing this idea to my wife for a couple years. At first she was skeptical, but has come around in the last six-months.

She dislikes [BIG understatement!] our neighbors [we live in a condominium]. She likes astronomy, and I have taken her to the small industrial park my studio is in and she likes how dark it is there at night. She also figured out she would not have to worry about me being in my studio alone [I rent a space in a multi-tenant industrial building].

Hey, its worth a shot!!

I'm sure she'll love it when the optics on her telescope are filled with dust!

[zool]

Louis stated: I'm sure she'll love it when the optics on her telescope are filled with dust!

Hey Louis .. you are more creative than that ..and thinking that I'd share my studio .. Here is the solution: that is what the rooftop deck is for.

Along with separate HVAC systems, separate entrances and excellent dust collection .. not a problem. Plus, the separate room inside on the first floor for wood machining.

so, where could there be a conflict. And besides, a small industrial building is a lot better piece of real estate than a house.

[louieatienza]

Louis stated: I'm sure she'll love it when the optics on her telescope are filled with dust!

Hey Louis .. you are more creative than that ..and thinking that I'd share my studio .. Here is the solution: that is what the rooftop deck is for.

Along with separate HVAC systems, separate entrances and excellent dust collection .. not a problem. Plus, the separate room inside on the first floor for wood machining.

so, where could there be a conflict. And besides, a small industrial building is a lot better piece of real estate than a house.

LOL she can't leave the telescope up there forever! The separate entrances seem like a bad omen, like a harbinger of things to come! Plus stargazing while hearing the whirr of the dust collector and buzz of the router is not my idea of a peaceful night outside! Plus where are the air handlers for the HVAC?

If you can pull this off I'd be a bit impressed, and shocked. You better delete your notification emails and internet history before she finds out your master plan...

[JerryBurks]

I thought I should give an update. The machine is basically finished for a while, but like most of my projects that means 95% finished. In the meantime, I added a rotary axis and started experimenting. This is a Chinese Harmonic Drive clone where I removed the 3-jaw chuck and replaced with a Oneway Talon chuck. The tailstock is obviously homemade but does a decent job.

[JerryBurks]

As a continuation of the previous post....

My first experiment project was the bigger sister of the 1" figurine that I had machined a few months ago from aluminum, but with simple manual flip 2-sided 3D-Cut (Vectric) path. This time I made it 5" tall from maple and generated the tool paths with DeskProto CAM. This software can handle either continuous rotation milling or multi-sided indexed milling. For the given geometry I chose the 4-sided indexed option.

I ruined 3 pieces of wood trying to get the Y and Z zero coordinates right. This requires extreme accuracy to avoid steps in the part when turning to another side. I still need to practice that and make it more reliable.

[Mauser]

That's very impressive! The figurine too. (What on earth has happened to my priorities??)

You must have a pretty high clearance between your table and the gantry for that, how much?

I would think that for a piece that has no flat sides on it, the continuous rotation would be less trouble.

[Drools]

Thanks for the update Jerry, I have a 4th axis on my wish list and your find looks like a great product. I want to make a chess set using one of these would make the process much faster.

[JerryBurks]

That's very impressive! The figurine too. (What on earth has happened to my priorities??)

You must have a pretty high clearance between your table and the gantry for that, how much?

I would think that for a piece that has no flat sides on it, the continuous rotation would be less trouble.

I have 8" clearance under the gantry and about as much z-travel. However, to utilize the full height I would have to move the spindle mounting plate up. It has 3 positions and is in the lowest now. But then I have to tram the spindle again and as long as I don't get such a humongous piece to machine I will avoid that hassle. Right now the chuck axis is 3" above the table and 6" diameter is probably more than I need for the foreseeable time.

The little figurine would not come out well with pure X-Z-A continuous rotation machining. That would not allow to remove the wood within the loop of the stretched-out arms. I am not aware of CAM software in the reach of hobbyists that can do continuous X-Y-Z-A machining.