"manufacturing" drawings ?

[Tmoose]

We submitted a (too danged complicated) 4 page drawing to a supplier as part of a RFQ. It was to finish machine dozens of diameter, grooves and flanges on a shaft machined from rough machined weldment They return a quote, that included a few items as exceptions.

Shortly after receiving the weldment They asked us up to their place to attend a meeting to talk about a simplified drawing they had generated. We approved their derived dimensions and signed their "drawing."

Now the project is almost done, and we have just been notified that the shaft will not leave their building unless we accept an "engineering" charge of a few thousand bucks because they had to generate a manufacturing drawing.

My questions (forgetting the hostage tactics) are -
1 -is it unusual for a machine shop to have to create such "manufacturing" drawings?
2 - If they chose to create a simplified drawing for their own use should we have to reimburse them like this?

Thanks,

Dan T

 

[looslib]

We put a note on our engineering drawings below the flat pattern stating that the flat pattern is for our internal use only. We do about 60% sub-contract on detail parts, but engineering doesn't know which parts manufacturing will sub out when they create the drawings.


"Wildfires are dangerous, hard to control, and economically catastrophic."
"Fixed in the next release" should replace "Product First" as the PTC slogan.

Ben Loosli
CAD/CAM System Analyst
Ingersoll-Rand

 

[BillPSU]

tunalover
My whole point is that these details have been left off of many prints. People making the actual drawings have no experience in shop processes and are only worried about getting the drawings out. On more than one occasion I've been told "we'll take care of that on the first revision" which is usually months after the new machine is already in production. Product design will already be working on the next variation of a family of machines while necessary changes languish due to lack of resources and manufacturing has to make do with marked up drawings, substituted parts, and reworking of parts in the assembly area. All of these are caused by management giving realistic leadtimes to introduce new machines and product engineering not meeting the due dates on designs and manufacturing and purchasing having to scramble. Of course the sales/marketing department already has orders for the original machine and the next machine in the family and states the customer won't accept any delays.

I hope more product engineering departments are moving experienced manufacturing engineers next to the design engineers to reduce the problems in new product startup and avoiding the fireman mentality of problem resolution on the shop floor.

Drawings with flat patterns and other aids can hopefully educate the product designers about process limitations and better meet the needs of other people within a manufacturing organization.

 

[ajack1]

“I hope more product engineering departments are moving experienced manufacturing engineers next to the design engineers to reduce the problems in new product start-up and avoiding the fireman mentality of problem resolution on the shop floor.”

Unfortunately Bill the exact opposite seems true in most cases these days in my experience.

We often get parts now that are impossible to make in practical terms. Currently I am looking at some press tooling that has some slots pierced in it that are 0.15mm wide to allow some tags to be formed, this is in 3mm material.

To get a new model we have been told will take six weeks out of a twelve week lead time so we have to “guess” what they are going to co me up with and try and “fix” it at the end of the project. This is from one of the leading manufacturers of car seats and slide ways.

The drawing is dimensioned fine and presented in a very professional way, but the design is rubbish. Not sure what this has to do with the original post but it is certainly is a major head ache and seems to be happening more and more.

 

[wes616]

“I hope more product engineering departments are moving experienced manufacturing engineers next to the design engineers...

We are a consulting firm for the aerospace industry... and have a Mfr Eng dedicated to laison between the various maufacturers that we work with and us in the design room. It works great, and I would love to see it happen more often. The benefit for us, is we have someone in the next room who can look over the drawings (withouth the usual eng vs. mfr attitude) and give us guidance regarding the capabilities of each of the different maufactuers we work with.

Our productivity has increased, to well offset his salary (because it seems, in a design firm, someone who is not designing is overhead) by increased efficency.

Wes C.

 

[Tunalover]

wes616-
Management take note of wes616's posting. Us design engineers have a lot to worry about and to expect us to know everything there is to know about an infinite number of mfg processes is unreasonable. Give us Mfg Engineers as intermediaries and and we all will profit!




Tunalover