Design & Manufacturing
Design & Manufacturing
(OP)
I would have titled this Design for Manufacturing, but I didn't what to bias people right off the bat.
I'm just looking to get a feel for what others are doing. This question deals with sheet metal design and in-house punch press fabrication, but could apply to anything designed where your resources are limited to certain manufacturing processes.
I'm wondering if you have created pallet parts or library features (or other) of your standard punches and dies for in-house fabrication, or design from a list of available sizes, or if you design what you need and let your manufacturing department worry about meeting your specifiactions?
In this day and age of competitve markets and constant drive to produce the highest quality item at the lowest possible manufacturing cost, it dawned on me that I should be designing with manufacturing (as well as assembly, maintenance, asthetics, durability, quality, etc) considerations clearly at the forefront on my mind. I'm just curious to see how others are addressing this.
I'm just looking to get a feel for what others are doing. This question deals with sheet metal design and in-house punch press fabrication, but could apply to anything designed where your resources are limited to certain manufacturing processes.
I'm wondering if you have created pallet parts or library features (or other) of your standard punches and dies for in-house fabrication, or design from a list of available sizes, or if you design what you need and let your manufacturing department worry about meeting your specifiactions?
In this day and age of competitve markets and constant drive to produce the highest quality item at the lowest possible manufacturing cost, it dawned on me that I should be designing with manufacturing (as well as assembly, maintenance, asthetics, durability, quality, etc) considerations clearly at the forefront on my mind. I'm just curious to see how others are addressing this.
"But what... is it good for?"
Engineer at the Advanced Computing Systems Division of IBM, 1968, commenting on the microchip.
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RE: Design & Manufacturing
Tehre are cases where need to push the envelope of what was currently manufacturable. We weighed those on a case by case basis. Usually meant buying more tooling or custom tooling.
Jason Capriotti
Smith & Nephew, Inc.
RE: Design & Manufacturing
No sense in making them go buy new stuff for each project, or try to figure out how to make something with what they have.
RE: Design & Manufacturing
RE: Design & Manufacturing
RE: Design & Manufacturing
Sometimes though, if time or cost does not permit acquiring the necessary tools or machines, a compromise needs to be found.
RE: Design & Manufacturing
In Limited Production, due to production priorities and capacity in the shop, some parts get moved to the Amadas. This sometimes modifing the parts so they conform to the exisiting tooling.
It seems to me that designs (sheet metal in our case) should be approached in a manner to allow the final parts to be made on either machine, especially if one or the other goes down to failure/maintenance.
So it seems that most of you haven't gone much past just referencing a hard copy of your shops tool list, except for Gildashard. Sorry Jason, but I haven't been able to use SW05 in any major capacity yet to see your contributions.
"But what... is it good for?"
Engineer at the Advanced Computing Systems Division of IBM, 1968, commenting on the microchip.
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?
RE: Design & Manufacturing
I am very interested in DFMA, although there is no company policy on it here.
I have bought a copy of the Doothroyd, Dewhurst, Knight textbook on it. There is a lot of stuff in there that is helpful to know.
I think the real issue is that you talk to your fabricators and assemblers and make yourself aware of what they can and cannot do. Most bad sheet metal drawings I have seen have +/-.005" tolerances all over the place. Sheet metals shops have told me they can bend to +/-.015".
I recommend doing complete, quality documentation. Production needs this anyway. When you break your assembly drawing down into clear assembly steps, or you write out assembly instructions, you pick out design flaws. A designer should never write instructions on how to winch an engine out of a car to change the spark plugs.
JHG
RE: Design & Manufacturing
Failure to design with the production process in mind will always compromise the quality of the product or drive up the cost when someone else downstream has to handle it for you.
I try to create parts that speak for themselves. Parting lines are implied by draft and other features so there can be no other way of molding a part except by what the features imply and require. This eliminates a tremendous amount of hassle when moving to production and I believe it is the obligation of every engineer/designer to do the same. Products simply cannot be produced without all these items being defined by someone.
Jeff Mowry
Industrial Designhaus, LLC
http://www.industrialdesignhaus.com
RE: Design & Manufacturing
It is a good idea to have some reference of machine tools to design by and tolerance the part accordingly.
RE: Design & Manufacturing
It is expeditious and wise to design to use as much existing and standard tooling as possible. However, if your design requires something different then it has to be acquired (tooling $$).
I've seen a few brand new engineers that can drive the snot out of a CAD system - great! But if the results aren't manufacturable then it is wasted effort. DFMA, baby! Design for manufacturability and assembly is an attitude and it can be learned. It should also be supplemented with an appreciable amount of hands-on experience. You learn a lot more about machining if you have to cut chips yourself than by watching a video. The extra advantage of this is gaining insights into what the processes are capable of. What are the things that can be done, but a lot of people don't know to specify. It makes the job just a whole lot more fun too!!!
- - -Dennyd
RE: Design & Manufacturing
1. A sheetmetal craftsman (who does know SolidWorks) bent samples of each material with each tool to reverse engineer the radiuses and k-factors. I placed all of this data into a spreadsheet, along with minimum flange lengths.
2. I then made part templates for each material by placing a simple base-flange and setting radius, thickness, k-factor and relief settings. Then delete the base-flange leaving just the sheetmetal feature and save as a template. I only did this for the most standard tooling, so if the designer needs a different bend radius they must consult the spreadsheet to see what is available with existing tooling.
The templates only work with the base-flange feature. Insert bends does not pick up on my default values.
As far as changing machines, the only quick solution that would work is if you could find settings that work for both. Otherwise, maybe a macro to adjust settings on the fly?
RE: Design & Manufacturing
RE: Design & Manufacturing
Here's what I have implemented in my company.
1- We have machines and tools for what we need to know their capabilities. The first aproach to design is to profit from having these tools (considered as standard tools). We know how to design according to these capabilities; there's not the need to by new machines/tools.
2- Even so we try not be to much attached to the actual machines and tolling available. We always give room to some innovation, as the maintenance of the standard processes and tools can result in a solution taht is not the most economic. Even during production (that is after the design process have long ended) we always keep our eyes open for an opportunity to change tools/processes (and revise the design accordingly) to get a cheaper product.
3- We involve the manufacturing departement in the design process so they can be advised of any production change (or even suggest this change). They will give cooperation with some tasks like estimate production costs, layout modifications, planning changes...
4- In fact we involve several departements in the design process as there are many things to look at (new components/materials to purchase, product transportation, new tools for test & mesurement, ...)
5- We keep standard features/palletes on the server, and SW is pointing there so everyone can use the.
Rrgards
RE: Design & Manufacturing
The problems are "created" when Manufacturing decides to move part A from one process (laser) to another (punch press) due to capacity issues in the shop. I won't discuss what happens when they decide to move products from manufactured to purchased, or vice versa....
Another problem arises from this as well, and that being in the past we standardized on imperical hardware. Now the design mandate is to use metric hardware. Very few of the existing tooling are the proper sizes for the new metric-hardware populated products (hence heavy use of the laser).
I also don't want to give a false representation of this being a "major" problem. It's jut something that has been overlooked in the past. I want to start bringing DFM more into the light.
"But what... is it good for?"
Engineer at the Advanced Computing Systems Division of IBM, 1968, commenting on the microchip.
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?
RE: Design & Manufacturing
We have the same problem. Sometimes, for several reasons, the manufacturing decides to change to an alternative manufacturing process.
We are not necessarely notified of this change. We discover this in cases where the quality departement reports deviations from drawings sepcs.
Then we will try to "negotiate" if this change will last forever (in this case the design will be revised) or not (in this case there's a report stating the conditions of acceptance)
Regards
RE: Design & Manufacturing
The idea of having a definative list of available tooling is novel to myself, and I'm sure, many others. I design sheet metal parts based on what tooling I have seen that our contractors have, tooling that they can modify or purchase readily.
At times we will bring onboard a new contractor and often this will mean modifying the design to allow for the closest tooling available.
Plant lists that our contractors make available never include details of punch/form tools etc.
Often a design isn't finalised until I take a concept drawing to a meeting with the contractor to ensure that they have the tooling capacity to fabricate what I have designed.
As the sheet metal fabrication is contracted at a fixed per-part cost my design priorities are 1.Fulfilling functional requirements 2.Ease of assembly of the finished product 3.Per-part cost of the outsourced fabrication.
Generally the easier the design is to fabricate the lower part cost we will see, but if it's a choice between ease of assembly of the final product or ease of fabrication of the sheet metal part then I'd design for the final product assembly since this is the costing which is variable and since sales won't live with variable retail prices this would mean we have variable margins....
...are we designers or compromisers?
RE: Design & Manufacturing
- Strength vs. weight
- Style vs. common parts
- Cost vs. quality vs. speed
to name but a few...Sometimes manufacturing must heavily influence design. Other times, appearance overrules all.
One compromise I never make: Never let your design tools' capabilities (CAD software, etc.) be the factor that forces you to simplify your design.
http://www.EsoxRepublic.com
RE: Design & Manufacturing
Let's say you like a 0.300 boss for some hard-to-define reason but a 0.320 does the job and your supplier has the tooling... it's a no-brainer.
If a 0.320 boss causes a design problem, you brainstorm what it would take to solve the problem. Then make a decision: design tweak vs $xx for tooling. The answer varies with every case.
Innovation is all about what's best for the product, not the designer's ego.
ko (www.ecooling.biz)
RE: Design & Manufacturing
I agree 100%. If we do not compromise then we are artists, not designers. But then, we would have not much we could manufacture or sell (how can we make those clocks working Mr. Dali?).
Regards
RE: Design & Manufacturing
Hey, I agree totally when it comes to an engineering compromise based on our professional judgement.
The compromise that leaves a sour taste in my mouth is where Marketing force an overly expensive 'Feature' on a product with a fixed budget. You as a designer are then often forced to produce a product where the remaining material costs are so low that the engineering standard is dropped.
Either that or you hive off the problem on to Manufacturing by leaving them with too small a budget to use skilled staff or adequete testing time.
RE: Design & Manufacturing
Star it
Regards...
RE: Design & Manufacturing
If you send out a print to be bid on by several people it may not be as easy to design the part for each set of tools but maybe you can be flexible if they call and say that they have a 0.203 punch and can they use that instead of a 0.210 punch if it saves you $0.75 a part.
I wouldn't however, allow existing processes and tooling determine everything. Again, it depends upon the market, but without pushing the envelope how do new processes and tools get invented?
RE: Design & Manufacturing