What are the two main differences between product design and machine tool design?
Right off the bat I think of two main differences between designing a product and designing machine tools.
TIME and DIMENSIONS
Product Design Time
When designing a product there may be numerous design reviews, you may spend a whole year or longer between conception to tweaking the design, testing it for market appeal, functionality, safety, costs… the list can go on. And many of these reviews don’t happen just once.
Then, when the product gets very close to completion, the manufacturing team starts planning for production. What parts will be assembled at what stations. And the Manufacturing Engineers and Managers start working on planning the design of the production machines.
Machine Tool Design Time
Once the product is getting close to release for production, there is a rush to get the machines, designed, built, and tested fast. The time line for a Machine can be as little as 1 month. Some of the more simple tools are created on the fly as the product moves into production and the need is discovered.
With Machine Tool Designs there may be only one or two design reviews. There is no need to make it look nice for the consumer, though safety and functionality are part of the design and review process. The whole machine design process doesn’t require as much time or as much… “going back to the drawing board”. (For those of you who are too young to have ever seen a drawing board, what I mean is in my experience there isn’t as much re-design occuring in machine tool design as in product design.)
One thing I hear from those who move over to machine tool design from product design is that in machine design the available stock size matters.
With each new manufactured part you need to think about using nice numbers so that the part can be manufactured easily with the least number of surfaces having to be finished.
A machine tool designer is always looking up stock sizes. And every time the designer has to change the size of a part they have to think about stock sizes and which surfaces will need to be finished.
When a machine designer can avoid finishing a surface, he/she saves build time and material, reducing the costs of the machine. So we must always check our stock sizes, and try to make the mounting surfaces stock dimensions. This way we avoid having to machine a nice mounting surface if we don’t have to.
When a piece of metal is saw cut, the surface is very rough and may not be square to the other surfaces. So mounting surfaces need to be stock or finished in most all applications.
Hot Rolled Steel is so rough even as stock, it needs to have all it’s mounting surfaces finished. We use Hot Rolled Steel for weldments only, and cut a minimum of a 1/8 inch off the stock size to make a nice finished surface for mounting other parts onto. We still make every effort to consider stock size when creating weld fixture parts.
Two companies that we refer to a lot to find out what stock sizes are available are Central Steel and McMaster Carr.
http://www.centralsteel.com for cold and hot rolled steel and aluminum and sheet metal. They have angles, tubes, rounds also.
http://www.mcmaster.com for harder steels or other metals not found in the Central Steel catalog such as A2 and 4140 PH (Pre-hardened).
So Product Design vs Machine Tool Design. If you have experience in both, what differences have you noticed?
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