Metric print English machines

[gcode]

One of our customers has started outsourcing

thier design and drafting work to India.

Now projects , models and blueprints will be

Metric.

 

I'm trying to work up a method for

dealing with this.

The only given is the gcode must be in

inches.

Normally I'd just bring the meteric

model into inches Mastercam and program it.

My latest project is a large complex part

80 x 60 x 10 (inches) with thousands

of features and a 24 sheet blueprint.

 

I'm looking for insight into how

other people deal with this.

 

The model is reference only and

will most certainly have mistakes.

The blue print will have errors a well.

I will have to check everything.

 

My simpliest solution is

to use Inches Mastercam and program as

normal.. with Analyze set to metric

output to simplify model checking.

 

any other ideas out there??

[spade117]

The machine doesn't have metric capabilities?

 

What you posted sounds like the best idea...unless you have someone that can redo the prints into english(seems like a waste of time).

[gcode]

quote:

---

The machine doesn't have metric capabilities

---

yes, but our machinist don't

 

I asked the customer about an English print

and got a very firm NO..

I going to try for a dual dimension print next..

but I don;t expect that to fly.. Its a busy

blueprint already dual dimensions would make it illegible.

[Tony35]

i dont deal with anything that complex for metric but what i do when i get a metric part and want inch output to the floor i will remodel the part in inch if i have time or just put in metric values in MC and give the value a mm after it and its converted

sorry i cant be more of a help on this

[Thee Rickster ™]

Gcode, Are all your tools Engligh/Standard.

 

Would this work, yet you will be programming in

metric? Program in metric and use the metric decimal eqivalant for yout standard tool sizes.

 

AS much as I hate metric, I don't have a huge numbers of prints to chechk to like you, therefore switching to metric 'seems' like the best option, maybe.

[gcode]

The machines, machinists, cutting tools

and measuring tools will all be English.

I'm just trying to work out a proceedure

to simplify my job and minimize the chance

of mistakes.

I was toying with the idea of programming metric

and switching to English for posting, but this

isn't pratcial for a number of reasons.

 

 

Normally, I'd remodel the part myself as that

is the surest way of finding model and blueprint

errors. I'm not going to get the time to do this.

 

Given past experience with this customer's models

and prints there will be mistakes.

This will be my first time with thier new

Indian contract designers. The model may

be a train wreck, it may be flawless..

I don't know... I'd prefer to find the mistakes

at my desk and not on the floor in a 6000 pound

block of aluminum.

[Bruce Caulley]

Having been on the other side of the same problem before, there is nothing you can really do except programme from model and then check everything with a conversion.

 

I never got around to trying it, but what about a scaled post? At the end of the day the numbers are just units. I thought once that I could just treat the inch measurements as MM and then have the post scale it up.

 

Is this an option in reverse that anyone has tried?

 

Bruce

[3R!< W3NG3R]

I was going to suggest the same as Bruce

[LaszloK]

I would build a solid model to verify the print dimensions and compare to their CAD model. I would work in inches inside mastercam BUT I would simply input the metric dimension with MM added to the end. This way, you are using their metric numbers, all of you internal work will be in inches, and after you hit the return key after the MM mastercam will convert your input to inches and you could make the inch notation on the print on the fly without having to convert everything ahead of time.

[gcode]

Normally, I'd build a model in SOlidWorks

with units set to metric.. then switch to english

and export it to Mastercam.. I won't be given

time for model building this time..

I think I answered my question while asking you guys for help..

Set analyize to metric and program the part.

That way I can check model dimension with

converting B/P dimensions

[Thee Rickster ™]

let us know the 'quality' of the data you recieve and the system it was done in.

 

Cheers

Rick

[MattW]

I think I am out of my league here, but if you have a model, I would program from the model. I would also bring the model into SW and do all my model inquiries there. You can set up the measure tool in SW to display dual dimensions, and you can copy and paste the results out of the measure tool. This seems to me the quickest way to both program and verify the model matches the print.

 

I am fairly sure the native units for SW are metric, but units are really arbitrary. I have never bothered to set units when exporting parasolids out of SW and into MC, and I do all my programming in English. It has always come in at the correct size.

 

I have a couple of SW macros to toggle the system units from English to Metric, that you are welcome to try. No guarantees that they will work for you.

[Leigh @ Kodiak]

quote:

---

The machine doesn't have metric capabilities?

_________________________________________________

yes, but our machinist don't

---

I really don't get this mentality. Machinists are supposed to be great at math, what is so difficult for them to use metric?

 

If a lot of your future projects are going to be coming in in metric, I would "suggest" to your machinist that they start getting comfortable with it.

[hugh jars]

Reading this forum I have been amazed at how many US firms are still using inches. I suspect that you will have to bite the bullet sooner rather than later and work in metric before your customers get an Indian firm to machine their parts.

 

Quote:

The machines, machinists, cutting tools

and measuring tools will all be English.

 

Do your CNC machines and CMMs actually care whether the data are metric or English ?

 

You must be planning to use metric tools if there are tapped holes, reamed holes, thread milling, formed radii, etc.

 

English measuring tools with metric drawings - you can tie yourselves in knots here. It's quite easy converting dimensions but it can be a bit of a bugger with tolerances - you end up with silly situations.

e.g 3.00mm , tolerance +0.02mm - about a thou but not precisely so.

Convert - 0.000787in

On an English micrometer you can round up to 8 tenths - and go out of tolerance

Round off to 7 tenths and struggle that bit more and spend an hour arguing about it.

Realize then that it depends on adding first to the nominal dimension: result 0.118897 - call it 0.119 No - that's out of tolerance.

Why bother ? Thousands of features on 24 sheets ?

Buy a metric instrument: 3.02

 

The quality of the drawings / models is a completely separate issue from the units that have been used. If they have errors in metric then they would still have errors after conversion to English. Work in metric, find the errors, report them to your customer, become a part of the loop and charge them for it.

Best of luck

[Matthew Hajicek - Singularity]

If you don't have time to make sure the model and print agree then you ARE going to have errors in the finished part. Make sure your boss understands this before he blames you for scrapping the part.

 

I've been doing something similar on a family of parts, though not as large or complicated as yours. I'm willing to get a jump start by programming the roughing from the customer's model, but for the finish I will only use my model that I made in Solidworks from the print.

[Guest CNC Apps Guy 1]

quote:

---

I really don't get this mentality. Machinists are supposed to be great at math, what is so difficult for them to use metric?

---

Got money to buy them all new measuring instruments?

 

I've got digitals that switch units at the push of a button. I don't see machinists with them out on the shop floor too often.

[Leigh @ Kodiak]

Maybe it's just a metric thing then, cause pretty much every shop I have been in had all the digis available. Even still, 9 times (or more) out of 10 that if the tolerance is so tight that conversion is inadiquite the part will go on the cmm anyways.

 

If these metric prints are going to become a trend, maybe your employer would be wise to start a program that would encourage the purchase of more up to date insturments.

[Guest CNC Apps Guy 1]

Personally I'd just rather see everyone go metric. But, I once worked in a shop that woudl run a part in whatever units the blueprint was in. Now, I've only ever seen one shop like that but it was a small shoppe with high-end equipment and top notch guys. It makes a difference.

[bigjohn]

I worked in a shop where all jobs and measuring instruments were imperial. I worked on a Russian metric centre lathe (excellent machine). I was the only one that had digital instruments and a calculator. Well, the place doesn't exist any more.

 

But in general, we don't seem to have problems with metric and imperial systems in the industry here Down under. A machinist must be able to handle both without any issues. Software and machines can.

 

 

John

[Mr. Wizzard]

quote:

---

Buy a metric instrument:

---

It sucks, but I've had to do complete drawing packages in metric by converting everything. I don't really have a problem working in metric, I just don't have the tools. I've spent years and thousands of $$$$ on the measuring equipment I have now.

 

I think the metric guys should send us complete metric inspection equipment sets if they're going to send us a metric drawing!

[shazam/TPP]

r&dcnc, they just won't send you the job then.

i see some of our guys struggle with metric as well, i don't know why. as everyone has said they're just units of measurement... done.

of course maybe the tool industry can have a cash for clunkers program to trade in your "inch" tools and buy the shiny sleek effecient "metric" tools.

[gcode]

At my shop we're talking OD and ID micrometers

out to 72" and venier calipers out to 120"

Serious money to replace

Then there is the metric/english mindset...

Some don't get and never will. It would not surpirse me in the least if we loose this part

cause some sleepy machinist miscalculates a

conversion at 3:30 in the morning.

 

I'm personally more concerned with the CAD/CAM end of it.

This company's models are done in Inventor

and sent to me as a step. Preivious models

were very sloopy

a 12.000 dimension might be 12.0036 or worse yet

a datumn plane that defines the entire model

would be off .0043

I could never use thier models for anything more that eyecandy.

 

Hopefully this was caused by coventering metric designs to english, but I suspect it was just sloppy work.

Maybe these new metric models built by Indian contracts will be better.

[bigjohn]

There may be one or two places where you can hire Metric instruments if you get the odd metric job. If you continually get metric orders then you must have the right equipment and thus be in the big league and competitive. That is if you want to stay in business. Ask yourself how many countries in the world use inches and how many use MM.

 

 

John

[gcode]

quote:

---

If you continually get metric orders then you must have the right equipment and thus be in the big league and competitive.

---

In this organisation, those decisions

are so far up the food chain I don't waste

my time thinking about them.

My opinion is neither requested nor desired.

Just draw the cartoons, post the code and

solider on..

[bigjohn]

Been there, mate.

 

 

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