CNC Inlay Machine Design

GBCues · Nov 4, 2013

Hey Guys,
I'm wanting to build myself an inlay machine. I like to DIY ths stuff - you really learn how to tweak it by building it. But I'd like to take advantage of the wisdom and experience of those who have already done it.
So I'm looking at the general design of this product:
http://pdjinc.com/
I've ordered their DVD and it should get here Wednesday. I will not be copying their machine sizes, but modifying to better accommodate cues.
It seems to be pretty well thought out - though the first thing that jumps out at me are their repeatablity/accuracy numbers when they're spec'ing a PC 7301 laminate router as the spindle.
However, I could start learning on their basic design and upgrade the spindle down the road.
I have my own CNC taper machine, and that is working well - 3 axes will be a new learning curve.
I have a brand new Gecko G540 controller and I'll use Mach3 - Mach4 when it comes out "soon"

I am looking at some new CAD/CAM software as well to work out the tool paths for the pockets and inlays.
And, of course, I'll need to add an indexing "headstock" and a fixed tailstock.
All comments welcome.
Thanks in advance!
:thumbup:
Gary

cutter · Nov 5, 2013

CNC design

Try to do more thinking and less buying. The more you can think out the entire design, the less money you will waste. Most people I know who did a home brew,
ended up with a pile of stuff they didn't need, or didn' work.
Be very leary of published accuarcy claims, they are usually tweaked.
For and inlay machine concentrate on X,Y. Z can be less accurate.(who cares if your pocket is .003 to deep.
These are my personal preferences.
Ballscrews over Acme(which ever you go with, make sure to match x and y)
square rails over round ( get as much preload on the bearings as possible)
cast flat plate over extruded alum.
good quality motor mounts with flexible beam couplers.
servo over stepper, (your 540 with steppers will work great, I just like servos)
quality 4th axis (drives me crazy seeing poorly aligned inlay work.)

Last but not least. Find a really good machine shop, and start buying them beer.

LGSM3 · Nov 5, 2013

cutter said:
Try to do more thinking and less buying. The more you can think out the entire design, the less money you will waste. Most people I know who did a home brew,
ended up with a pile of stuff they didn't need, or didn' work.
Be very leary of published accuarcy claims, they are usually tweaked.
For and inlay machine concentrate on X,Y. Z can be less accurate.(who cares if your pocket is .003 to deep.
These are my personal preferences.
Ballscrews over Acme(which ever you go with, make sure to match x and y)
square rails over round ( get as much preload on the bearings as possible)
cast flat plate over extruded alum.
good quality motor mounts with flexible beam couplers.
servo over stepper, (your 540 with steppers will work great, I just like servos)
quality 4th axis (drives me crazy seeing poorly aligned inlay work.)

Last but not least. Find a really good machine shop, and start buying them beer.

cant get much better advice than this right here. I agree with every point Steve made.

I'll add that a good plan, A heavy solid base help too. Also, a g540 and steppers will move the world if its attached to quality, properly aligned components. Try to stay away from 8020 if u can

TomHay · Nov 5, 2013

Gary,

Just one old guys opinion.

Your spindle should be fixed, the only movement should be the Z to come up and down. The More accurate the spindle AND the more RPM's the smaller the bit you will be able to use which can lead to sharp points

The X and Y move the table. This part should be a BULL, solid as can be. If the weight can shift the table one bit during movement you better be prepared to be using a lot of black and black glue.

Today the W (Butt Turning) is refered to as A, make sure your screw for this is divisable by 360.

Not hard to build at all, your money will be spent on the best rails and the Spindle.

Good luck Bud, have fun.

RBC · Nov 5, 2013

Actually, I prefer the moving gantry design as opposed to a strictly moving table.

To have a moving table, you will need an axis that is close to 7 feet long if you need to work the length of the cue. The inaccuracies of an axis that long can boggle the imagination.

I really do recommend a good spindle. Shop ebay for an NSK, a Precise or a Kavo. You'll spend some money, but it will be very well worth it.

I'm OK with steppers, just don't go crazy on speeds or accelerations. I'm also fine with acme leadscrews. Just make sure you have good anti backlash nuts. Keep in mind that, unless you buy used or surplus, any ball screw under $1000 is going to be rolled instead of ground. Rolled screws will invariably have some backlash in them. The only ball screws I've liked were ground screws. Most systems do have backlash compensation, but it's useless on a low friction axis typically used on cue machines.

Mach4 looks to be more of a commercial controller than for hobby uses. I'm certainly not a hobbyist, but Mach3 can currently do anything I need it to do. And I do quite a bit of macro programming, special scripts, and background functions called brains. I don't currently plan on using Mach4.

GBCues · Nov 5, 2013

I do appreciate everyone's comments - keep them coming.
I haven't bought anything yet, except a design DVD.
Lots of planning yet to come.
Gary

conetip · Nov 5, 2013

For the same section, Steel has 3 times the rigidity or Young's modulus than Ali.
ie , a box section in 2 inch square, with a 3/16 wall section, has the same stiffness as a 2 inch box section in steel with a 1/16 wall section. Both will weigh approximately the same,unless you used CrMoly , then the CrMo steel will be more rigid.

I like a lot of what they have done in their design and lay out.Like Royce pointed out, a moving gantry takes up less foot print in the shop.
Advantages of Ali construction, is often easier due to the enormous range of Ali extrusions, The down side to Ali, is when it is tied to steel, it moves around with temp change, like a bi metal switch does. If your shop varies more than 15 deg C, then the changes can be measured. Like the Taig type lathes with a steel dovetail onto an Ali base.
Just some more food for thought.

DanO · Nov 6, 2013

cutter said:
Last but not least. Find a really good machine shop, and start buying them beer.

Very strong advise Mr Klein....

Things I’d change if I build another: Have a flip up table to level the forearm for the Z axis. Larger spindle to be able to cut V points. Full table gantry for the X axis instead of my back one.
Things I’d do the same if I build another: Design all your bolts top down and accessible for dialing in your X and Y. Use Mic6 aluminum for the bed to make sure it is flat. Kirk lead screws & zero backlash nuts. Square linear rails and bearings. 5C collet index so you can choke up on the forearm to eliminate cue vibration. Keep Mc2 on my good side.

Honestly I had more fun building mine than I’m having using it. Good luck with your venture.

RBC · Nov 6, 2013

DanO said:
Very strong advise Mr Klein....

Things I’d change if I build another: Have a flip up table to level the forearm for the Z axis. Larger spindle to be able to cut V points. Full table gantry for the X axis instead of my back one.
Things I’d do the same if I build another: Design all your bolts top down and accessible for dialing in your X and Y. Use Mic6 aluminum for the bed to make sure it is flat. Kirk lead screws & zero backlash nuts. Square linear rails and bearings. 5C collet index so you can choke up on the forearm to eliminate cue vibration. Keep Mc2 on my good side.

Honestly I had more fun building mine than I’m having using it. Good luck with your venture.

What do you mean?

He's useless!

Just kidding of course. I've learned tons from Jim. If only he had a crappy job. Maybe I could get him to come down here and work for me.

Royce

GBCues · Nov 6, 2013

This is the kind of stuff I was hoping to get - thanks!

DanO - can you expand on this: "Have a flip up table to level the forearm for the Z axis"

:thumbup:

Gary

Travis Niklich · Nov 6, 2013

I think he means a sine plate. That should point you in the right direction

Brickcues · Nov 6, 2013

He means to have an adjustable table so you can tilt the 4th axis so that it is at 90 deg to z axis.

I have a tail stock that I had a machine shop make that is adjustable so I can tilt my 4th axis and keep it at 90 deg to z so that it is flat all the way across the forearm. When you inlay points if it is not flat then you will go to .125 deep on one end but way less than that on the other as it is at an angle. You could do with 3D program and get Z to change as it moves but then you have to draw depth and make more measurements. A lot easier to do in 2D and have flat surface for pockets.

cutter · Nov 6, 2013

cnc inlay machine design

A few more thoughts.
Don't just look at machines in your price range for ideas. Haas, Hyundai, Hurco all have online literature on what makes their machines different.
See how the big boys do it, then adapt the principals to your comfort level.
Think about work stations on your table. Dedicated areas that you don't have to
tear down and re install as you go about building. If your system is
accurate enough, you can do just use work offsets and cut way down on set up time.
Build a cue step by step in your mind and see how it interacts with your machine.
Make sure you have plenty of room to run air, vac and extra electric.
Simple things like where you have your keyboard/computer, worktable
can make your life either great or suck. Depending on your spindle think about
handling the noise.

Travis Niklich · Nov 6, 2013

Brickcues said:
He means to have an adjustable table so you can tilt the 4th axis so that it is at 90 deg to z axis.

I have a tail stock that I had a machine shop make that is adjustable so I can tilt my 4th axis and keep it at 90 deg to z so that it is flat all the way across the forearm. When you inlay points if it is not flat then you will go to .125 deep on one end but way less than that on the other as it is at an angle. You could do with 3D program and get Z to change as it moves but then you have to draw depth and make more measurements. A lot easier to do in 2D and have flat surface for pockets.

That's what a sine plate is

GBCues · Nov 6, 2013

Brick, Travis:
Thanks - that makes sense now.

Steve:
You've been more than generous - and the suggestion to look at the high-end machines is well-appreciated.
:thumbup:
Gary

Mc2 · Nov 6, 2013

Hey Gary, I have not chimed in yet because you are getting great advice. I too believe that building your own machine is rewarding. I also believe in learning from other peoples mistakes. Lol. Stick with quality materials. For the record I use all stepper motors and they are accurate enough for what we do. You could go servo motors however there is not a huge advantage as Mach 3 does not use the feedback.

Jim.

Brickcues · Nov 6, 2013

Gary,

What are you going to use the machine for? Is it just for inlay work or will it also be used to taper?

conetip · Nov 6, 2013

GBCues said:
This is the kind of stuff I was hoping to get - thanks!

DanO - can you expand on this: "Have a flip up table to level the forearm for the Z axis"

:thumbup:

Gary

Have a look at older Deckel Milling machines.A lot had adjustable tables. They could be adjusted for milling tapers and compound angle milling. Usually +- 15 deg on the X axis(long axis) and upto 30 deg on the short axis

.
But an easier solution is to mount a lathe onto the machine bed, and make that to be adjustable in the heights at the feet. This allows you to incline or decline the assembly.

GBCues · Nov 7, 2013

Brickcues said:
Gary,

What are you going to use the machine for? Is it just for inlay work or will it also be used to taper?

Hey Brick,

Well - yes! LOL I currently have a CNC "taper bar" built onto my Hightower style cue lathe and it works well. So this project will start out in life as an inlay machine. But I'm also thinking "Geez, this is a pretty hefty expense in time and money for a few little squiggles at each end of the butt!"

:grin-square: LOL
And like other guys do, it might get used for other small projects, but it might end up doing some tapers as well.
I get as much satisfaction out of designing and building the machine(s) as I do building cues.
How's that for a non-answer?:smile:
Gary

GBCues · Nov 7, 2013

Mc2 said:
Hey Gary, I have not chimed in yet because you are getting great advice. I too believe that building your own machine is rewarding. I also believe in learning from other peoples mistakes. Lol. Stick with quality materials. For the record I use all stepper motors and they are accurate enough for what we do. You could go servo motors however there is not a huge advantage as Mach 3 does not use the feedback.

Jim.

Hi Jim,
Oh I knew you couldn't ignore a thread with "CNC" in the title.
And YES I'm getting great input from many guys here.
THANKS again to all!
:thumbup:
Gary

CNC Inlay Machine Design

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