"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

 

[ajack1]

It is not usual but not unheard of to create a drawing, especially if the current one is ambiguous, or certain parts of the design are not achievable in the view of the manufacturer. However most companies would insist on doing this themselves for their QA systems, what happens if you require another and do not wish to use the same company?

Sometimes we “modify” models for companies, sometimes we charge sometimes we do it for “free” as a good will gesture depending on the size (cost) of the project. We would always make this cost known and get an order to cover this to the prior to doing so.

Basically they are pulling a fast one, I assume you have a contract to produce the part(s) they will be legally obliged by that, at least in UK law. They should have informed you and raised an order prior to doing any extra work.

 

[moldcore]

Reminds me of a lawyer who once sent me a $40 bill for a form letter to inform me he was no longer representing me.

Was anything stated in their Quote for such services? Your only obligated to pay for what was quoted and on your P.O. Since you signed a drawing that you understood to be an internal document only, and was created before you gave approval to create the drawing, I don't think you're liable. However, not much you can do if you want your part back, I guess. You could tell them you can't pay for the part until the part is inspected by an independent inspector off site, then take 120 days to pay for the original quoted price and make them take you to court for the 2K. <G>

 

[mrainey]

I spent twenty years as a manufacturing engineer in machining job shops, and spent hundreds of hours creating manufacturing drawings from customer blueprints. The drawings were designed to eliminate any confusion about what the machinist and inspector was to do at each operation. Special tooling tolerances and other "out of print" considerations were spelled out if needed.

I never heard anybody mention billing the customer for those drawings.

Manufacturing Freeware and Shareware

http://mrainey.freeservers.com

 

[musashi99]

As mentioned it is not unusual to to make process drawings. However they should have mentioned up front (not to mention in the meeting where sign of of it)that here was an NRE charge Also, you can make a lot of drawing for a few thousand doillars

 

[aamoroso]

I am suprised by the whole story. The manufacturing drawings are pretty common things for companies. We create our own drawings for everything we make, our design or the customers. If the customer supplies a drawing we re-create our own regardless of the job. Most of the reason is for our in-house designed computer system which automates much of the manufacturing and database functions. Even still we do not charge engineering fees in most instances, unless the design work is a huge amount of labor. The cost of creating the drawings is something we choose to eat because our automation makes up for the expense and much more.

I would be cautious of paying the fee at this time and question them why this wasn't discussed. I would inform them that if they had required a better drawing, that you could have provided them with one and they made a choice to create the drawing that you agreed was up to specs. I would also ask if this is common practice for them and then tell them you would hate for this to be a regular expense considering other shops aren't charging you under similar circumstance. If they don't back down at all, pay it and RFQ them on your next job but don't give it to them. After several rejections of thier quotes they will most likely ask why? Tell them you have been adding a couple thousand dollars to every quote they send and that puts them out of the job. Doesn't really solve anything but if they don't back down on the charge I wouldn't send any more work to them. On the other hand if they show you in writing that there is a fee that can be charged, eat the fee and be more careful.

Fill what's empty. Empty what's full. And scratch where it itches.

 

[1plus1]

I have worked in a job shop since 1983 and to answer your two questions, in my opinion, I would have to say "No" to both. However, question two should be answered by a lawyer. Most job shops that I know of, including ours, quote a price up front taking in consideration many factors, including any time for generating a maufacturing print. A few thousand dollars "surprise" like this is highly unusual.

 

[Pressed]

No and no. And they did it for the RFQ right, that is before the job is awarded!?

All pricing should be up-front unless that is the arrangement. A vendor not on the side of his customer is showing a sign of being complacent and it usually gets worse from there.

My first question to the vendor would be "how long do you want to supply my company", maybe not. Anyway, you might ask them to finely detail the bill for the prints and let them know (prob in writing) that you will be comparing it to the hourly data you already have generated on the prints you sent them.

I have worked with vendors that didn't complete all thier work, as agreed, so I sent them 75% of the bid. On later jobs I could tell that they just added that anount back in. Vendors that we could all do without.

_______________________________________
Feeling frisky.........

http://www.tailofthedragon.com

 

[BillPSU]

The couple of thousand may be your price for another educational opportunity from this supplier. You need to understand the importance of this supplier to your company and the ease at which replacing the supplier can be replaced.

You didn't give us any idea of the cost of the shaft or if it is a custom designed shaft or what.

These additional costs should have been approved before continuing to make the part and should have at least been dicussed at the approval meeting.

 

[ornerynorsk]

They should have been upfront with any costs. The fact that they are holding your part hostage is the sign of a very poor shop.

 

[DAVIDSTECKER]

Sometihing else that might be going on is that the shop under bid the job and this is a way to recoupe their loss.
I've had shops come back to me AFTER they recieve my material and say that they mis-understood the drawing or that they thought the parts would be different than what they recieved.

 

[TVP]

My thoughts are essentially the same as everyone else. I understand the need to have a profitable business, but holding a part hostage over an engineering charge for their internal drawing is absurd.

 

[EngJW]

We have had companies take our worn out pencil and paper drawings and create complex solid models, and there was no charge.

Sometimes a company will ask for a change, or they will find a mistake and insist that we revise the drawing before they make the part.

Some designers will make a drawing of the final part but will leave it up to the shop to determine the process. The shop may make its own drawings to show different stages in the machining or may have drawings to cover such things as before and after plating or heat treating. If you tried to put all this on one drawing you would go nuts, as every company that quotes it will ask for something different.

 

[moldcore]

We also make solids from old paper drawings because that is the way things are done now. We advise our customers at the time of quote that there may be an extra charge if the electronic model is not available. But it stops there, any drawings used for internal use are part of the cost of doing business. If changes are made to the original quoted drawings or solid models then yes we do charge them accordingly, depending on what stage of manufacture it's in of course.

 

[Tunalover]

Folks-
Don't forget that an engineering drawing is supposed to portray the end-item and not the processes used to achieve it (see the definition in ASME Y14.100M). If you find a need to write down intermediate stages and/or step-by-step instructions then don't pollute the drawing. Instead create a separate document (call it what you want but a good name for it is "Work Instruction"). Of course if the end-item is simple enough then you won't need any more documentation.

By adding extraneous, site-specific process detail (",,,install screw using ACME 1034M hydraulic screw driver...") then you make it so that the document is useful only to the manufacturer who prepared the notes!

People don't like to be told HOW to do their jobs. They'd rather be told WHAT has to be done and then be free to utlize their resourcefulness, expertise, and creativity to "do their thing."

If you were to send such a drawing to an outside source for quote he will either "no bid" or overbid. Why? Because you are telling him not only WHAT to make but also HOW to make it. Even if the manufacturer provides an acceptable quote, you will bury yourself along the way with paperwork to document all the exceptions. A messy scenario indeed!

I've spent a good part of my career trying to keep the engineering drawing where it belongs: in Engineering!






Tunalover

 

[BillPSU]

Tunalover
I understand your position but I have experienced the problem of what you describe. Put it on paper/electronic file the way you want it to look and let some manufacturing people figure out a way to make the part. An example is a casting. Is the casting drawing part of the "engineering" drawing? Is the flat pattern drawing part of the "engineering" drawing? Are subweldments part of the "engineering" drawing? The answer is most of the times it should be.

I also like discussions about Bill Of Materials (BOM) because in the eyes of a product engineer that is the way to build an assembly. When parts are moved to other assemblies they say you are not making it per specs, when in actuality you have just moved the part to another part of the BOM.

 

[Tunalover]

BillPSU-

For sheetmetal parts do you actually show flat patterns on the ENGINEERING drawing? Typically the fabricators would rather do their own flat pattern. If you impose the flat pattern on a mfgr then you are tying his hands.

For weldments, I don't know about you but the mfgrs I've dealt with would rather see the end-item only. By including also all the gussets, ribs, beams, etc. in your ENGINEERING drawing you are forcing the mfgr to do it only the way that you have drawn it.

Of course it's OK to have MANUFACTURING drawings (better called work instructions) if you want to document a site-specific way of making something.



Tunalover

 

[wes616]

Turnalover,

I agree regarding the flat pattern. It seems each shop that we work with (since we are a consultancy we tend to work with a lot of mfrs) do flat patterns a little different. Givig a Flat pattern is a hinderence to them; however, occasionally there is a SPECIFIC REASON for mandating a certain way of bending metal that DOES need to be controlled by engineering, by all means give flat patterns then.

Wes C.

 

[BillPSU]

What happens when holes are too close to the bend and the holes distort. The manufacturer then drills the hole when many times hole distortion is OK. Rectangular hole in a curved part. Is the rectangle measured around the radius or through the part? The flat pattern would answer the questions. Ractangular hole is it cut before radiusing the part or after and is the distortion on the lip allowed?

Flat patterns are not necessary on an engineering drawing as long as questions like this are answered on the drawing with notes.

 

[Tunalover]

BillPSU-
Any self-respecting design engineer or designer would add a note allowing local distortion around the bend OR would design the part so that features are well-away from the bend. If the note is left off then shame on him:
A. the mfgr will have to contact the buyer,
B. the buyer will have to consult with the designer,and
C. the buyer will have to add and exemption to the PO and reissue it.

I know I'm "preaching to the choir" but bad design is expensive becasue it affects so many people downstream.


Tunalover