Messages

1

General Mach Discussion / How to set "Safe Z"?

« on: December 07, 2008, 11:36:21 AM »

I'm confused about the Safe Z thing. Seems to me that it'd be a good thing to have as I can then simply hit my "Safe Z" button on the controller and have the spindle move to a in good height to change tools... but how do I set the Safe Z in Mach 3?

I've found a "Global Settings" window under the Config/Safe_Z Setup.. but don't understand what the settings mean/do. Seems like the most important one is where you enter the Safe_Z amount. But what is that amount in reference to? The table? Home position? Soft limits? Is is negative or positive from these?

I guess I'm really confused about machine and work coordinates as the DRO's don't say which they are.

BTW, I just got this great CNC controller (pendant, mouse, whatever the thing is called?) http://www.randyray.com/TxMicro/ which is the reason why I'm now keen on getting my CNC setup together better. Check it out - all you do is plug it in and it works. No software, no batteries. Pretty slick for $225!

-- Rich --

2

General Mach Discussion / Re: Surface grinding?

« on: May 19, 2008, 09:02:01 AM »

I've been checking out some of those machines/sites. Incredibly expensive and overkill for what I want to do? One good thing though - I just found out that there's a big machinist trade show just down the road from me called Eastec which opens tomorrow. Talk about good timing! There seems to be thousands of manufacturers and vendors there. Does anyone have suggestions on who I should check out for small CNC surface grinders and software to run them?

-- Rich --

3

General Mach Discussion / Re: Surface grinding?

« on: May 17, 2008, 03:23:10 PM »

Concertinas are played all over the world though mostly in English-speaking countries like the UK, Ireland, Canada, the USA, South Africa, New Zealand, Australia.... Accordion reeds are made very similarly, and of the same materials as concertina reeds are, and accordions are played pretty much everywhere. Rust isn't much of a problem at all. Even for accordions in Florida.  :-)

-- Rich --

4

General Mach Discussion / Re: Surface grinding?

« on: May 17, 2008, 11:52:17 AM »

OK now you bring up the 2.5D approach to grinding the reeds. It is an easier approach BUT very "slow" in comparison to the 3D approach. THat process Could be done on a GOOD SG with CNC controll. New machines are available.

By "that" process do you mean the 2.5D or 3D?

ALSO it will require a GOOD cam package to produce reliable program code at that level of interaction. You are moving from a fluid 3d move to a series of simple moves to emulate the same effect. It gets complicated in the code required.

So it sounds like I should be able to get a machine to grind reeds with a 2.5D package? Show me the way!

SO if you are going to have to HAND tune each reed anyway then the extreme griding tolerance is really NOT a factor. Just a good repeatable profile down to a usable tolerance.

Yes. I'm hoping that we'll be able to achieve results within 20 cents.

In the beginning you mentioned 1000s of reeds but later mentioned  only a few 100 a year. (;-) There is a big difference in what you can get away with machine wise there.

Hmmm... Sorry about the error/confusion. There are 44 pitches of reeds we regularly use (and rarely about 24 higher and lower pitches) and our first years run of concertina-reeded boxes is expected to at least 30 boxes. Each box usually has 2 same-pitch reeds... so 2 reeds x 30 boxes = 60 same-pitch reeds/year. If each blank we grind can be split into 30 reeds that means we'd need 2 blanks x 44 pitches = 88 blanks ground for our first year's production. Just 88 little 4" blanks of steel will yield us 2600 reeds. That's rock bottom minimum. As some of our models have more than two notes of the same pitch (each note has 2 reeds) then more realistically we'd be needing maybe 100 planks = 3000 reeds.

If we were to replace all the accordion reeds we're using in our current models of concertinas with concertina reeds then we'd have to come up with about 350 more ground blanks = 10,500 reeds.

?? Are your reeds stainless steel???  or just tool steel. How do you deal with rust if not stainless ??

Our reeds are spring steel (not stainless, not tool steel). We don't deal with rust because rust isn't an issue unless one plays constantly in extremely humid conditions (like on a boat on log ocean voyages) in which case you can get concertinas with stainless steel, brass or phosphor bronze reeds (which are very rare). In my 30 years of making and repairing accordions an concertinas I've come across only 2 cases of rusty reeds, and both were due to the boxes being submerged in a basement flood and left to moulder for weeks.

-- Rich --

5

General Mach Discussion / Re: Surface grinding?

« on: May 16, 2008, 06:02:45 PM »

While they may not specifically support surface grinding, I can't see how if you can control X,Y and Z from any software you would not be able to adapt that to grinding if you had a machine set up for CNC.

That's what I would assume... except that *I'm* not able to do that. I'd have to hire someone to figure it out, set it up for me, and teach me how to make (convert my CAD to) g-code files for it.

The real problem may be the diameter and width of the wheel in relation to the contour your looking for.

I think that's solved. The reed grinders I know either have the spindle tilted at about 2 degrees, or a titled bed, or a beveled wheel... the idea is that only a point of the wheel touches the blank to be ground. Lots of coolant and only very small point grind per pass keeps the steel from loosing it's temper. My friend who makes reeds says that for each pass he moves Y .0005" until the end of the blank and then starts over but down Z .0005" for the next series of passes. My understanding is that this is pretty much what all the concertina makers do (that use a SG).

how do you produce the reeds now?

We don't. Our current models use accordion reeds which we buy in bulk from Italy. We *have* made our own concertina reeds but they've been by entirely hand filing (only for replacement work) and some by working with machine shops to have them produce them (no joy).

I noticed you mentioned hand finishing a while ago in one of your posts, you may allways have to do that operation anyway since each batch may have a slightly different property.

Yup. Reeds always need to be hand finished. Even the best made ones in the world from the most sophisticated machines. We'd be very pleased if we'd be able to come within 20 cents (100 cents = 1 semitone) off the machine. Reeds are so sensitive that you could take a reed and it will have a different pitch if put in one part of the instrument or another part - so they have to always be fined tuned anyway. We expect that.

To be honest I had never thought about this sort of thing before, now you have me wondering how Honner has made harmonoca's all these years or are they all flat reeds?

All those reeds have a very sophisticated and exacting multiple curvature. Hohner has an incredible wealth of reedmaking knowledge which they guard extremely well.

-- Rich --

6

General Mach Discussion / Re: Surface grinding?

« on: May 16, 2008, 05:41:09 PM »

Looking at some of the radius involved I believe you would be best served by a belt grinder.

Now that's an interesting idea. I've heard that the more modern Italian reed companies use belt grinders but I never knew what they were. You're mention of that got me Googling around. Very interesting. I'll continue to check them out.

-- Rich --

7

General Mach Discussion / Re: Surface grinding?

« on: May 16, 2008, 04:54:44 PM »

Any cam program will work with what you are trying to do. Check out Bobcad

Thanks for the reference... I just checked them out... and talked to them... and their software does NOT do surface grinding.

you only need to put out G-code if you plan on using Mach and you need to control 3 axis and are only going to perform a 2 axis interpulation(x&z) the y will be bumped over at the end of stroke.

This all is very frustrating. I've called 5 CAM software companies today and none of them do surface grinding. Is it that there is no market for producing software that writes code for SG? I wonder why.

If all else contact me I believe I can write these for you.

It certainly may come down to that.

Your cost would be feasible if you were doing the conversion yourself.

Conversion for what a manual or automatic SG to CNC? Conversion of DXF to g-code?

I believe any quality grinder will work (although you want gibs not ball ways, its a finish issue) Brown & Sharp and Thompson are a few more SG to look for

Thanks... I'll check those brands out.

-- Rich --

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General Mach Discussion / Re: Surface grinding?

« on: May 16, 2008, 03:53:27 PM »

Well, once if find someone ELSE to build/modify a machine for me... then yes, all the parts I'll be making are incredibly similar. Maybe I can hire someone to code the first one and I can use that for a template for the rest of them.

9

General Mach Discussion / Re: Surface grinding?

« on: May 16, 2008, 03:49:10 PM »

Wow, I had no idea. I've been using Sheetcam which seems like great software and it cost only $150. So a 3D program costs 70 times as much? Now I'm really lost.

-- Rich --

10

General Mach Discussion / Re: Surface grinding?

« on: May 16, 2008, 02:37:20 PM »

2).  CAM program, How much you wanna spend? I use OneCNC XR2 Mill , but there are others Master CAM, Gibbs, Delcam, etc. you can set your cut depths in these programs, and they will all take a 3D model and machine it.

I just called all those software places and every one of them have no info on their sites about surface grinding and when I called them they said that their software won't work on CNC surface grinders. I don't understand what's going on?

I can convert one for you, BUT, In your case with all the concerns involved, I would build a custom job. How much you want to spend?

I hope to spend under $10,000. Is that at all realistic?

-- Rich --