Trying to turn a sheetmetal shop to machine shop?
Trying to turn a sheetmetal shop to machine shop?
(OP)
Hi all,
Recently, I started as a CAD engineer in a sheetmetal fabrication company. In my first week, a QC manager came and asked me to go over future drawings carefully for one particular company. He said if necessary, better to say we can't do it to the company. As they used GD&T specifications for all their sheet metal parts. And some of the tolerances/ spec. is quite high, which resulteed some parts were rejected. To tell a long story short, they tried to make fabricated sheet metal parts & bolt it together to construct a frame assembly (which another precision machinery sit on the top of it). However, due to imperfection of bending of flanges and hole locations positioning, the assembly was off.
I understand this is a challange to our shop as some of the parts will not work, if straightly go by the spec., but on the other hand, I am questioning if there is a straight yes/ no answer to this question. As I saw there are similar parts made some time ago (on the drawing database). Being a new guy, I don't want to reject the potential purchase order right away, as the management will get mad on me.
My department has a production manager (he basically in charge of everything technical under the roof, he is pretty busy), and a project manager (he is more focused on administrative tasks and schedules).
Any thoughts on this? Any advices help.
engmechs
Recently, I started as a CAD engineer in a sheetmetal fabrication company. In my first week, a QC manager came and asked me to go over future drawings carefully for one particular company. He said if necessary, better to say we can't do it to the company. As they used GD&T specifications for all their sheet metal parts. And some of the tolerances/ spec. is quite high, which resulteed some parts were rejected. To tell a long story short, they tried to make fabricated sheet metal parts & bolt it together to construct a frame assembly (which another precision machinery sit on the top of it). However, due to imperfection of bending of flanges and hole locations positioning, the assembly was off.
I understand this is a challange to our shop as some of the parts will not work, if straightly go by the spec., but on the other hand, I am questioning if there is a straight yes/ no answer to this question. As I saw there are similar parts made some time ago (on the drawing database). Being a new guy, I don't want to reject the potential purchase order right away, as the management will get mad on me.
My department has a production manager (he basically in charge of everything technical under the roof, he is pretty busy), and a project manager (he is more focused on administrative tasks and schedules).
Any thoughts on this? Any advices help.
engmechs





RE: Trying to turn a sheetmetal shop to machine shop?
On the other hand, perhaps those customer tolerances were created by another CAD Engineer who probably also did not discuss them with a Process Engineer. This may be an opportunity for you to go back to the Customer and have a talk with them to relax their drawing tolerances to something your shop can produce.
TygerDawg
Blue Technik LLC
Virtuoso Robotics Engineering
www.bluetechnik.com
RE: Trying to turn a sheetmetal shop to machine shop?
It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.
RE: Trying to turn a sheetmetal shop to machine shop?
Years ago when I had a similar job to yours we would send back exceptions to the tolerances on the drawings that we didn't think we could meet with the quote. For example a hole dimensioned off of a bend that was originally specified at +/- 0.003" might be changed to +/- 0.010" or 0.015". If the customer was ok with the exceptions we did the work to the new tolerance, if not we didn't get the job. This worked better for us than rejecting the job as it still gave us the opportunity to win the work.
GD&T can be difficult in sheet metal depending on what they chose for their datums, hopefully they used holes or edges and not flanges.
As a side note, see if they will let you work at different jobs around the shop to better understand what you are programing for. If you can spend a week or two working on a turret punch and a laser you will make life much easier for the operators!
RE: Trying to turn a sheetmetal shop to machine shop?
B.E.
You are judged not by what you know, but by what you can do.
RE: Trying to turn a sheetmetal shop to machine shop?
While never plan A, sometimes drilling holes/machining features after forming can be the only option.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Trying to turn a sheetmetal shop to machine shop?
engmech
RE: Trying to turn a sheetmetal shop to machine shop?
You had better believe it, If you dimension from the outside of the part. the press brake folds from the inside.
B.E.
You are judged not by what you know, but by what you can do.