[deanrach]

I have attached a NIMS (National Institute for Metalworking Skills) part print for this poll. Given the attached print my programming and inspection skills are best described as:

[thainz]

I could hand program this part and inspect it. I would prefer to draw it in solid works and program it in Master Cam though.

[miljnor]

I am curious why you want to know if we are competent?

A lot of the people that come to these sights are exceptional individuals and might not be good for a general consensus of the Machining populace in your area.

[deanrach]

miljnor,

I'm not quite sure I understand your statement.

[miljnor]

i made an assumption that you were polling to see if the machinist in your area were well qualified or maybe how well qualified you are.

And I was just stating, that the people on this board probably represent the top 15% of the machinist community, in terms of professionals.

So maybe it wasn't the best place for a comparison.

just a guess and maybe incorrectly.

[dertsap]

gd & t has opened a huge door for engineers to really make a drawing mess of a simple part

[miljnor]

what?

I thought they had a pretty good handle on that already!

[dertsap]

goes along with the typical communication gap , they don t understand what is meant in the words

i don t care about your calculations ,it won t fit !!!(chair)

[miljnor]

My partner is one of the best I have worked with (maybe its the fact that he has a masters, I don't know) but he still cannot wrap his mind around 3 dimensional space and the way a cutter has to move!

I mistakenly say sometimes "thats very hard to do" and what I really mean is: Its not hard, just long and tedious, and, oh ya, EXPENSIVE! He then shapes up and understands!

I guess I should take language lessons!

He still tries the old: "the other guy I worked with could make anything!"

Yep so can I but it will be exponentially more expensive with the amount of 3d programing and machine time!

[Geof]

...He still tries the old: "the other guy I worked with could make anything!" ...

A good reply to that is does the 'anything' include money?

[miljnor]

Ya, its always nice to make some of that!


unless of course your talking printing it up, then I don't know anything and I never saw you before in my life!

[tobyaxis]

This is a good test for a beginner that I'm teaching on another Forum. You can guess what I voted. It is a shame that this industry looses so many young people these days.

As for the other two topics, I don't know what you talking about

[chrisryn]

I have done the requirements for that NIMS part and cert. It was actually easier than some of the program problems I had to do for the instructor.

[deanrach]

chrisryn,

I agree with you. It's not a difficult part. And, like anything else, if good machining practice is observed, the rest falls into place. Some people tend to get a bit overwhelmed by the use of GD&T - in this case, I must say it was rather excessive.

I require students to do a 100% inspection on the surface plate. We then follow-up with an inspection using the Renishaw OMP40 on one of our HAAS MiniMills.

[Bowman]

GD&T is practical so long as the requirements are practical to the item being made. Many times you see prints with tolerances spec'd to some tight limits for areas that are not even remotely important to making a part successfully. Everytime you add more and tighter tolerances you add time, costs and headaches. Simplicity in dimensioning working drawings so that all dims can be obtained without clutter are key along with knowing where true tight tolerances are needed. Some folks just like to spec tolerances in the ten thousands of an inch range on every single feature simply because they can and I think they believe it makes them look more intelligent. These folks usually set the tolerance limits in the drawing setup and then proceed to apply them by default to everything instead of limiting it to the areas where it is critical.

Anyone every done any Descriptive Geometry? M.C. Esher was a master of this and his work proves that just because you can draw something hardly means you can build it as drawn, even with no GD&T's

Bowman

[planar39]

are you after a free quote here? i can name that song in 53 seconds! I also appreciate the others point of view that mgmt/eng. dosent want to deal with-how long it actually takes to make a quality part. So for you mgmt ppl. listen to your top machinist, when he says i can drill that hole in 1 min, and then bore it with an endmill in 1 min and it will be approx within the #$%^ tolerance you want to freaking achieve

basic GD if you have +- .005 on either way, x and y . cut that in 1/3 .
so you now have .002 deviance either way, see chart (not provided)

[WayneHill]

I understand GD and T. Too bad that designers don't understand it and how it relates to the manufacturing process.

It is my thought that GD and T and SPC were thought up by over educated
professors to sell to under educated management types.

The truth is - It does not add value to the part!

[chrisryn]

Just to give an idea. I am a student at a tech school for both CADD/CAM and precision machining/CNC. The info on GD&T in the cadd class is short and limited. In the machining class the basic print reading GD&T has twice as much info then there is the GD&T class after you complete programming. So as a machinist I have learned more about GD&T than I have in the cadd class.

[todd71]

Based on the poll I just want to add to the question "What is GD&T?" It stands for (Geometric Dimensioning & Tolerancing). Here's a link to a basic overview http://www.engineersedge.com/gdt.htm

[deanrach]

Todd71,

Thanks for the contribution.