O/T Flexible Manufacturing (Cells)_

[jspangler]

Hi

Just wondering if anyone could recommend any books on cell based or "flexible" manufacturing?

 

Thanks

 

John

[chris m]

Run, do not walk, away from anyone talking about cellular manufacturing

 

just my .02

[jspangler]

Hi

Why??

From what I've read so far, it seems like another one of those buzz words that pops up every couple of years, and I wanted to see if there was anything to it?

 

Care to explain?? Real world experience with it should be worth more than some $50 book from Amazon.

 

 

Thanks

 

John

[Guest CNC Apps Guy 1]

John,

 

Come down to my shop. I'll show you a cell that runs 300 hours a week (two machines at 150 hours ea) With all due respect Chris, you're dead wrong. This will be how American Manufacturers stay competitive. It's the only way. We can't beat other nations labor rates or their lack of regulatin but we can sure run lights out manufacturing operations.

 

Just My Personal Experience

[CNCme]

Good Day,

 

I think there will be many views, but

I have to Side with chris on this one.

 

IMHO I have been involved with

cell Mfg for over 15 years, maybe before

it was created...or refined, or is it yet.?

 

The decline in large order (quantity) type

Jobs has made it hard to justify the capital

Investment for not only the base cnc machine,

But all the outside equipment to complete

The cell. And in order to be efficiently

“Flexible” the more base machines or cells

the better. This reflects back to the lesser

Or smaller “large revenue “ jobs that fuel

your cells.

I haven’t spoke to Chris on this but if he

Has worked on this 1/3 as long as I have,

He will agree

 

And I also think the books dont tell the "Hole"

story

 

Tony G

X Beta site

Almost Employed Senior Programmer

N.E Massachusetts - Southern New Hampshire

_________________________________________

End mills and tooling are like The "AMMO"

And coolant and chips are like the enemy

Under your boots as you advance in the

Manufacturing Battle

--------------------------------------------------

[chris m]

There are multiple definitions of the word 'cell' that work better or worse, depending on your product. To me, a true manufacturing 'cell' is an area that manufactures a single product or small family of products ONLY and has machines, tooling, fixtures, gages, operators, etc that are specifically dedicated to that product and process. In medium- to high-volume production or in production environments with a low product mix I'm sure this works well enough but in high-mix or low-volume applications I think this concept sucks. We fight this battle in my shop all of the time, particularly since we are the subsidiary of a Japanese company. Since our main components are similar in nature the management types are constantly pushing to have lathes, VMCs, and gearmaking machines all shoved together in cells to get a 'flow' of product. The only problem is that with 5, 10, 50 piece lots by the time you finish setting up, there ain't any flow to go through the pipeline.

 

I will consistently pump more product with the mills over here and the lathes over there, guaranteed. The time-in-motion, 'lot size of one' types talk the talk, I've never seen them walk the walk in this type of environment.

 

If you've got repetetive work that can keep those machines running ALL of the time, go for it; otherwise you'll be dragging the machines back to where you had 'em in six months.

 

C

[jspangler]

Hi

OK, well back to the original question, since I have no background in even understanding what they are referring to when they speak of "cells". DOes anyone know where I can get any info on this?? With the direct competetion I am fighting against from China, it seems like James has a point. But, I manufacture and sell my own products, and do very little job shop or outside machining work, maybe it will benefit my company more than a typical machine shop?? All I know is that I need something to level the playing field a little.

 

Thanks

 

John

[chris m]

John

 

I'm pretty sure that I can dig up a couple of titles around here somewhere. If you do a internet search about 'cellular manufacturing' or the 'Toyota system' or something you're bound to come up with something. I'll poke around tomorrow as I'm due to lock the place up here in about 1/2 hour and I've got to get some info ready for the day shift guys.

 

C

[CNCme]

Good Day,

 

James,

I am very happy on your accomplishment...but, this cell,

does it only make one part?

 

Can you switch to another part with with

very little effort and also get the same

results.

 

If a piece of equipment in the cell goes down

( a major piece ) could you re-create the cell

in another location without disturbing

production.

 

These are all facets of manufacturing flexibility.

The more facets the more brilliant the stone,

And the harder to produce…but, the most rewarding.

 

At a large die cast job shop

I have helped build 30 cells that are "almost" totally interchangeable. The key word is

"almost". The word flexible has its varying degree.

The truth is, they will never be totally

interchangeable.

 

J, the answer is the book might not help you

unless you use the theory " the more you

make, the better cells will work"

HTH

 

Tony G

X Beta site

Almost Employed Senior Programmer

N.E Massachusetts - Southern New Hampshire

_________________________________________

End mills and tooling are like The "AMMO"

And coolant and chips are like the enemy

Under your boots as you advance in the

Manufacturing Battle

--------------------------------------------------

[jspangler]

Hi

OK, well that doesn't sound like ti would work to good around here, but my machines are set up in a small semi circle, and we do have dedicated fixturing... If that's the basic "theory" behind this type of manufacturing, we're already doing it. I use sub plates on all my machines, and am able to switch jobs quickly and pump out parts to feed my production guys on a daily basis, without having much overstock, or falling behind.

 

Wow, feels good to be doing SOMETHING right.

 

See Ya

 

John

[Travis B]

I think there are two differant types of cells at issue here. One being a work cell and the other being a machining cell. What James has is a cell where two or more HMC's are linked together with a "train" that moves any number of pallets back and forth between operator stations, holding racks, and the machines. A work cell can have many types of machines in it to improve the flow between the machines.

[biss03]

we use what i would call a variation of what chris and james are decribing. and to be honest, i'm pretty sure it was demanded that the machines be set up this way by the customer once they heard our concept. We are a high volume machine shop and just about all our jobs run in "cells". most have 2 haas verticals with possibly a drill press but not often. a few are set up with a haas vertical and a mori horizontal with wash tanks and gaging tables all in the "cell". we do have the ability to change these "cells" quickly from one job to the next and could very easily move from one cell to another (know this from experience). so i would agree with james on this point even though our "cells" may be different. of course chris has a point to: if your running small quantity setups, it may not benefit you as much.

[Guest CNC Apps Guy 1]

Travis nailed it. The term "cell" is used a bit loosely. My "cell" is 2 HMC's (Horizontal Machining Centers) linked together by an AGV (Automatically Guided Vehicle).

 

Q: I am very happy on your accomplishment...but, this cell, does it only make one part?

 

A: Currently it makes 6 different parts, but the number of different parts I can make at any given time is limited only by the number of pallets/fixtures on pallets.

 

Q: Can you switch to another part with with

very little effort and also get the same

results.

 

A: Yes.

 

Q: If a piece of equipment in the cell goes down

( a major piece ) could you re-create the cell

in another location without disturbing

production.

 

A: If one of the HMC's goes down, I can take it out of the system with a switch and all the work will be diverted to the working machine. If the AGV goes down, the whole thing is paralyzed. Lukily Mori Seiki is down the street.

 

The computer handles the schedule.

 

As for what you're doing John, my type of a setup would be overkill, but I think if you can swing it, a 400mm - 500mm Horizontal would allow you to run a lights out second shift. Horizontals a bit more expensive up fornt but they soooooooo pay for themselves in so many ways. If you're interested, drop by my shop and we can talk about it.

[CNCme]

Good Day,

 

James,

As we have all shown, the customer drives the

the configuration of these cells. Everyones

configuration will be diff. I believe all

of us could write books about this subject.

 

John,

Sounds like you have the right idea on your

own unique cell system.

 

Thanks for everyones informations

 

 

Tony G

X Beta site

Almost Employed Senior Programmer

N.E Massachusetts - Southern New Hampshire

_________________________________________

End mills and tooling are like The "AMMO"

And coolant and chips are like the enemy

Under your boots as you advance in the

Manufacturing Battle

--------------------------------------------------

[jspangler]

Hi

Thanks for the responses.

I actually intended to buy a Horizontal last year, but the wife said NO!@! It was going to be a Haas, so it's probably better I didn't buy...

 

I _Barely_ managed to talk her into the tree VMC that I just happened to find on Ebay with a pallet switching system. Now, a year later, the machine has paid for itself 3 x's and I just got the switcher set up about 2 months ago. After reading everyones responses, I think the deciding factor is how well you know your business and customer base, and how much of a commitment you are willing to make to stay in the game. My competition does NOT play fair.

 

Now if I could just do something about the price of steel....

[Guest CNC Apps Guy 1]

quote:

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...My competition does NOT play fair...

---

Who's does??? That's why you gotta automate, go with high part densities on your tables so you can get longer cycle times and higher yields over a 24 hour period. When I have my cell fully loaded up, it'll run for 30 hours straight without a single light or soul in the building! That's the way to compete! 2 guys, 1 shift, 6 days - 300 hours of machining time.

[Philcott]

James,

 

I am curious about how you get the parts checked with such high volume and low operator hours. Do you just do a random sampling or are there others doing QA checks on the high volume runs?

 

Phil

 

(Are you getting any sleep with the baby around?)

[Guest CNC Apps Guy 1]

quote:

---

...Do you just do a random sampling or are there others doing QA checks on the high volume runs?...

---

Yes. Both. Our parts are not very close tolerance. ±.010" is the norm for location and we have a couple of holes that are ±.00025Ø But they are reamed and S/C reamers last a LONG time if run at the correct feeds and speeds in al;uminum. The guys will generally check one or two from every pallet and they visual every part. The process is so stable and my operators are so good, our scrap rate is far less than 1/16 or 1%. I think since January, we've scrapped out less than 15 parts, and we've run thousands. QC does a sample check as well.

 

Sleep.... yeah I manage to get some here at work! j/k... actually I'm averaging about 6 hours including an 1 hour nap when I get home. Occasionally I'll take a nap at break and lunch if I'm especially tired. That'll net me another 45 minutes total between lunch and break.

[McRae]

Check this publication - I have not reviewed this book but the caption reads like what you are looking for.

 

http://www.sme.org/cgi-bin/get-item.pl?05200756&2&SME&

[F. JAVIER]

I think you should take James offer and have a look at his shop because once you see a cell work in progress you will realize how you can apply it to your shop. In our cell the concept of the cell applies to the machines (they are linked and have the same tooling so a job can be transferred to any other machine if the other is busy. The fixtures are built around the same concept (location bushings and bolts around the same pattern) so that any fixture can be moved to any pallet, tombstone or face you choose and the cells are close to an are that is of need, (toolcrib, inspection, etc) the same principle can be applied to a smaller shop, the key is that the "principle" or "concept" must be followed.

HTH F. Javier

[Guest CNC Apps Guy 1]

quote:

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...our scrap rate is far less than 1/16 or 1%...

---

I MEANT to say 1/16 of 1%

 

James teh me needs typing lessons or a spell checker.

[DrewG]

Jspangler---What type of "Cell" are you looking for: Horizontal machining center's, or a "Cell" consisting of several different machines, for example milling, turning, grinding, etc..?

I, too, own my own business, and manufacture my own products. I started with Haas vertical's and recently purchased a Makino A66E with a two tier, 8 pallet, linear cell. I can expand it up to 12 machine's and over 200 pallets if need be(wishful thinking), or just add more pallets, or another machine. There is another option called a "pallet pool" whereby, a single machine is involved with anywhere from 4 pallets up to perhaps 36. These are generally less expensive as they don't require an expensive "cell controller".

At my business, we run 100's of different parts in quantities ranging from several hundred to several thousand. For me, I required "flexibility". I had to have fixtures that would be able to run all my parts, be fast to change over, and be able to be brought online from my vertical's quickly. After speaking with experts from so many manufacturer's, the conclusion was that 8 station vise towers were the way to go. I purchased 8 Toolex/TECO 8" , 8 station towers. They have quick change parallel sets that can hold parts as deep as 2.000's or as little as .100. They can be snapped on and off with the twist of a screwdriver, and have .0002 repeatability. They also have aluminum or steel soft jaws that twist on and off the same way, as well as full "carvable aluminum or steel" jaws. The towers also accept a large fixture plate (10.000 wide x 30.000 tall per side) that you machine anyway you require, and can be snapped on or off almost as easily.

With the cell controller, I can schedule any part I need, and keep the spindle making chips on current jobs. As soon as the tower is set correctly for the new part/s, the controller send's the job in. For my shop and my guys, the cell was the best purchase I've made. The flexibility and the ability to run "JIT" jobs is unsurpassed. I can run 20 different jobs with various operations at the same time, and the cell controller keeps track of everything. The operator's just do what the screen tell's them: flip part's over, load new parts, etc..

On another note, compared to just a few years ago, the price for the cell's have dropped tremendously. They are affordable to small shops now. The one cost that hasn't and won't come down though, are the fixture's. At 25K a tower, I spent over 200k on fixturing alone.

Depending upon your needs, a cell could be the best way to go. I wanted to pick up a 3rd shift every night, as well as on weekends. I pay one guy $100.00 to come in for an hour on Saturday to load the towers, and I get anywhere from 2-12 hours of machining. I also have problems finding employees, so if I had purchased 3 vertical's instead, I would be stuck trying to put "bodies" in front of them. These are just a few things to consider.

If you would like to discuss it further, drop me an email, and I'll give you my number, or if you close to NJ you can stop by.

[Jimmy Wakeford from Barefoot CNC]

Not to make you take a step back, but I do think you should read "The Goal" and "Who moved My Cheese". Celluar mfg is great if you understand why you are doing it and not followng buzz words. Also if you have employees I'd suggest "The one minute manager meets the monkey".

 

Jimmy teh its easy to splain it to everyone but the geeterhead in the mirror.

[Jimmy Wakeford from Barefoot CNC]

FYI:

 

James's set up is pretty swwet for what I would call production runs. I think By the time he is done setting everything up he'll be able to txt mssage the machines to switch over themselves. (He;s spooky with that sort of stuff. Betwwen Nc programming and machine macros...spooooky)

 

Tbrucke has 30 production type cncs (mori's, mazaks, daweoes, etc) and the average lot size is 2.8 . That is pretty cool for an ol'country boy.

 

Tbrucke also uses macros on some machines, and yes Mr. Materra he has trained all his operators to read.

 

Well its 3:30 here so I need to get ready to get on the road.

 

Jimmy teh Dang this is tooo early!

[Guest CNC Apps Guy 1]

quote:

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...I think By the time he is done setting everything up he'll be able to txt mssage the machines to switch over themselves. (He;s spooky with that sort of stuff. Betwwen Nc programming and machine macros...spooooky)...

---

 

I'm actually working on something so that if I send an e-mail to it, it will reply with the status of the system... all from the comfort of home.

 

James teh technology is there so I might as well use it!