Hello i'm new here! Faceting

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Hi there,

My name is Christian 33 and im from the Netherlands, i came to this forum becourse i cant find any in the Netherlands.

At the moment i am building a faceting machine and i could use some help, im sorry if my question is to straight. For now i can do the most for making my machine.

Im going to build a seven axis cnc faceting machine, i will also do the electronics and the software for controling the machine. I already have buyed manny parts that i will use on my machine and all parts are high/verry high precission parts. I calculated for example my z axis with an precission of 600.000th of a mm. I know this is only theoretical and not the real deal, but 1000th of a milimeter should be more than ok :- )

Are there more people that have build there own cnc faceting machine?

By the way it is going to be a hobby machine! And the sizes that the machine should cut is from less than a milimeter up to 100 milimeter.

Manny thanks,

Christian

Ps. Nena is the name of my daughter!
 
Gday Christian
Sounds like a hell of a task ;)
Im sure many will be eagerly following the progress of your effort
Thanks for sharing
Thanks for joining ... And ..
welcome aboard :p
 
Welcome Christian

Have given thought to the concept but have not seen it done before. Theoretically if you can control the precise radial and tilt angles and depth of the progressive polish, all should work.

In my limited experience, the quality of your cutting medium will be important, as a single oversized particle will render a theoretical cutting depth calculation faulty, resulting in scratches in the final finish, an additional fine polish depth programme step should be considered.

Precision in the radial, angle and vertical movements will be essential to prevent a spiral of facets resulting in meet point errors.

Like your thinking and would love to see some progressive build photos and commentary.

Good luck.

Wally
 
Hello Wally, Sandta and Jaros,

I have made an axis image for the axis i'm going to use.

These are my axis:

slijpmachine_assen.jpg


X: To move my cutting head from the cutting disc to the polishing disc. (Normal Precision)
Y: For moving over the lapidary discs. Dont know what discs im going to use yet, 8" or bigger. (Normal Precision)
Z: To get everything lift up and for cuttung the stone in layers (High Precision)
Y2: To be able to reach the cutting table for small stones, could also be used lifting up the stones. (High Precision)
Xr: To rotate the stone on the dop stick. 360 degrees (High Precision)
Yr: To rotate the machine head from 0 degrees to 180 degrees (High Precision)
Zr: To rotate the machine in clock wise ore counter clock wise on the cutting disc/polishing disc. 360 degrees (High Precision)

The spindles i use are from known party's as THK, NSK, HD or INA. For the axis X, Y and Z i will use 25mm in diameter anti backlash ballscrews. The axis Y2 i use a 10mm ballscrew. Also i will use lineair guides with blocks for support. I Stil searching for them but due the price of them i need to wait if i see the good sizes. 5 of the 7 motors wil have Harmonic Drives. This keeps the backlash away and my holding torq wil be higher than the motor wil give. A normal stepper motor has a holding torq of 3Nm with the Harmonic Drive in place my nominal torq wil be around 170Nm (Newton Meter). So it is almost impossible to get a movement you dont want.

I maybe already have my cutting head complete! I have a some complete units from a precision robot that i could use. Here is a photo. The motors and the bearing you see is just for example there not at there place :- ) but it is an idea.

Img_1794.jpg


To give you a idea of the size of my machine, i have a another photo of the bearing.

Img_1787.jpg


I will post some more images when i have new parts or when im starting to build. (if you want?!) I took 2 years for completing my machine. But i already have 60% of the parts! I can almost begin with building!

As a young boy (12) i learned faceting from my dad. But i had other interests in that time and didnt took it serious but now im older, i just love those shining beautiful facetted stones. I have now the skills to build my own! Also my dad had build his own. But i also like robotics, electronics, programming and chemistry. And guess wat! I also search with a metal detector ;- ) Got a XP Deus and im hunting for over the 20 years now ;- )

Greetings,

Christian

PS: Sorry for my bad english! But you should try it in Dutch ;- )
 
Welcome to the forum Christian.I would be very interested to see some of the things you have found with the XP Dues.Your english is fine Christian.Gelukkig prospectie mijn vriend.
 
Hi Eldorado,

Oke, i will post just one find that i found a month ago. Its a bronze axe from 800bC i wont post more finds in this topic, but i could open a new topic in another threat. The overal finds here are from 20st, 19st 18st, 17st and 16st century and you can also find older but not in Drenthe where i live. But it is possible to find older thing here but then it is from the bronze time/stone time.

Img_1567.jpg

Img_1570.jpg


All finds from the century's between 1500aC till 800bC are rare here (in the province Drenthe).

Greetings,

Christian
 
Gwahhhh this axe is a killer!!
Bronze age finds are rare anywhere.

I'm heading back to France soon, I still hope to find an axe... so far my best find of the bronze age is a nice arrow head.
 
It is! I would love to go hunting in France for a time! And also in Australia! When i will go to Australia i would go for hunting some gold! :- ) and stay there for a month or three! Hehehe! This bronze axe is now one of my best finds ever! Hope to find more at that spot where i found it.
 
That machine looks hectic ! So basically it will be an automated machine ? Looks very ... Engineered :) hope it comes together for you, would like to see the results . It's the Dutch blood that stirs the inner facetor , the quest for precision ,even if there isn't a need , to the extent an individual shall take it , curse our heritage ! :)
 
Yes yes yes mate
Very interested to see your build
That axe head is bloody awesome !!
Would love to see more of your finds
Your english is certainly better than my dutch ;)
No problem understanding what your saying at all
 
Hello Sandta,

Okey :- ) i will keep you up! First im going to build my first stages of the machine. The first thing i need to do is sell some things i have laying around to get some $ uhm euro's.

I also have some feets for my machine, also ripped off a robot :- ) got 4 of them and will build the basis on those feets. I first need all of the linear guides. These are very pricey... around 200 euro's a pair. But i have buyed them before for 50 euro's each so 100 euro's a pair. If i have these parts it could go fast :- )

I just completed my CNC milling machine so i can also mill my own parts in aluminium. I have build this machine in one year the most of the time was waiting on parts... machine weights 280kg, completely designed by myself, also all aluminium milled parts. Size 1300x1300x600 mm

Img_1823.jpg


I also have thougth about automatic dopping, but that is for later :- ) Im going for it, this is a thing i want to do becourse i can also get some money out of it (i hope). It will cost me around 2000 euro's to complete the faceting machine and then the rest (finishing toutch)... Only the drivers to drive the steppers will cost me 700 euro's... so i must wait on some parts to get it cheaper.

I will post all changes on this thread :- )

Christian
 
Today i flattend my machine bed, im going to try to mill my first part out of aluminium tomorow or something :- ) I hope it will work. I'f got a small video online on youtube of the machine at work :) but couldnt post a movie yet! Also tomorrow i get some parts by post, 2 of the 3 spindels, i already have the 3th spindel that one is 1056mm long.

If im rigth these are the calculations of the precission movements: (An stepper motor works with steps. for 1 revolution the motor must do 200 steps. It is also possible to make half steps or even quarter step etc. Best setting for a stepper is 1/1, 1/4 and 1/8 Higher settings will result in step loss)

X: 10 / 200 = 0,05 mm per step (Speed is 10mm for one revolution)
Y: 5 / 200 = 0,025 per step (Speed is 5mm for one revolution)
Z: 5 / (200 * [1/4] * 50) = 40000 = 0,000125 per step (Speed is 5mm for one revolution)
Y2: 5 / (200 * [1/4] * 50) = 40000 = 0,000125 per step (Speed is 5mm for one revolution)
Xr: 360 degrees / (200 * [1/4] * 50) = 40000 = 0,009 degrees per step
Yr: 360 degrees / (200 * [1/4] * 80) = 64000 = 0,005625 degrees per step
Zr: 360 degrees / (200 * [1/4] * 80) = 64000 = 0,005625 degrees per step

The rotating can smaller if i go to 1/8 of a step. Pretty Precies :)

Greets,

Christian
 
Yes! My ballscrews have arived! First one already cleaned, now the second one... cleaning and placing back 132 steel balls... i hate this job! If you ever buy these kind of ballscrews and you want to clean them, be pacient, dont get mad! :mad: :D

Img_1827.jpg

Img_1828.jpg


These are for my Y axis (the long one) and my Z axis (the short one).

Greetings,

Christian
 
:rolleyes: Makes me ponder the following;

Managing heat generation and athe inherently slow rate of material removal for polishing whilst chasing a desired depth to ensure geometric perfection may benefit from an oscillating step algorithm.

Installing a pressure guage or lap motor resistance circuit could be used to verify the completion of polishing to a step

An adjustable lap platform, combined with a pressure/resistance sensor may be able to ensure the lap is true to the stone swing axis across the lap. I understand the best final polish takes advantage of swinging the polish across the lap to maximise the variability of polish medium cutting across the face in different directions. Or can a single contact point using precise control deliver a similar result :rolleyes: does uneven lap wear become a redundant consideration :rolleyes:

Thanks for bending my mind Christian :cool:
 
I've heard some automated machines can give a yield at a dismall 3percent ! Hope you can improve on that . And wally , automated machines decide when the polish is finnished , not the quality of it . I think some use the " record player " tequnique , where the "tracks" are moved by alternating where the stone cuts ,in a small track , to maintain Acuracy are moved every other stone to " the next song " if you know what I mean . Would be great for parcels of small stones . I think his project is great , yet I think the interest is more on the engineering side as opposed to making a perfect stone . But looks like thought and skill has gone into with gusto . Respect for the leviathan you are creating :)
 
Hello Wally and Kingsolomon,

I have looked at all the automatic machines, there all made for speed! The one i going to make isn't made for speed but for accuracy. Also the techniques they use is al straigth. For example all the machines i could find use all a single stepper for driving the facethead. This meens that the accuracy of a rotating step is set by the driver, probably there settings are set high what is resulting in faults. This is not only for that single stepper but for the complete machine. And they are limited by the actions they do. I use Harmonic Drives for accuracy, these parts costs on the second hand marked around the 300 euro's, new 2000 euro's each. I use 5 of them on my machine. I also use large spindels and high accuracy lineair guides. I'f i buyed all parts new the machine would cost me around 40.000 euro's. Exclusive software!

What about polishing. I can program everything i want. My idea was to let the machine first polishing and when it is done i can look at each polished flat and set a note to the computer to redo some of the flats or even do al again. Even giving pressure is not any problem. The machine can give more preasure then a man can do! A 4Nm stepper can lift 50 kilo's at the Z axis. With the Harmonic Drive it is in theoretic 50 times of 50kg.

I will make my software on trail and error, then i can see what i can and what not! I couldnt find any machine who also made there own software. (I Lie, have seen 2 that had ther own software, but very very limited and it looked like that is was standard cnc software).

Im going to build first all axis and then the cutting table and the polishing table. And what about heating, is is possible to cool through the facetting head if i must. There are many solutions for many problems.

Mayby its me but i didnt fully understand both post.

Oh, wat about the algorithm, the parts i use are all anti-backlash. that means, if i turn the motor or turn the motor clockwise the driven part is turning direct without any stops in it. So if i turn from 45 degrees to 0 degrees and back the enresult wil always be 45 degree.

Also the cutting disc and the polishing disc are meassured if im going to start. Even the stone wil measured wat the largest size is.

Im not finished yet :- )

I also thougth about an microphone in the cutting head to measure what the sound is, if im toutching the disc, cutting the disc etc. There are many techniques i could use and i can use them and program them all :)

Wally: i can move all axis to the point i want. If i have to swing the stone over the polishing disc, i can do that, if i need to use multiply axis i can program that. Im not limiting by one point. Another example, if there is a groove in the polishing disc, i could even avoid the groove on the disc.

Kingsolomon: I dont know what the end results will be. If it will be perfect or not, i just wanna see if i can make a machine that can facet stones. But im very curious if i can get the same results as a handmade faceted stone.

I know, also my machine will have some flaws. But its a start ;-)

Christian
 

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