We are living in a society that provides us with instant gratification in so many ways that we have come to expect in in almost all of our interactions. On top of that, if you, as the customer, know anything about machining processes, you might guess that the cut time for your part will only be 10 or 20 minutes, or even 1 or 2 minutes. Knowing that, it can be frustrating to hear that it will take a week or three to get your parts back.
Sure most machine shops could turn that part around in a few hours if they had the tooling and stock material on hand (which they probably do.) They could do it if all they were doing that day was sitting around waiting for you to walk in.
Why does it take 3 weeks?
How long it takes to make your parts depends on number of factors that you probably haven’t considered to this point. Below is just a short list of things that might impact the time it takes to make your part(s):
- the quality of your design,
- the number of parts in the queue ahead of yours,
- the number of parts you need,
- whether or not the stock material on hand,
- the quality of your design,
- the complexity of your part(s) and the fixturing required to hold it (them,)
- whether or not the tooling for your project is on hand, and, also,
- the quality of your design.
The quality of your design
The quality of your design may be the most important factor in getting the parts you need when you need them. I can’t count the number of times I’ve finished making a part for someone and then they tell me they need to change the design and I try hard to ask good questions to make sure I’m making the part they need rather than the part they asked for.
A quality design doesn’t need to have solid models whe FEA analysis, it doesn’t even need to have dimensioned and toleranced drawings that conform to ANSI or ISO standards, it simply needs to have enough information to convey the design intent to the manufacturer with no ambiguity. If you do this any cranky old machinist can make you exactly what you ask for.
Depending on the complexity of what you are asking for with your design a sketch on the back of a bar napkin may be all that is needed, but I’ve found in most cases that I would like you to give me a dimensioned drawing with tolerances specified for all 2 dimensional parts and a drawing and a solid model for all 3 plus D parts.
This speeds up the process for creating the manufacturing plan for making your parts. It speeds up the process for designing and creating any specialized fixtures your part(s) might need and it absolutely makes it easier to create any CNC programs required.
First in First Out (FIFO)
Most machine shops process orders on a first come first served basis, and they need to have a week or two of work scheduled in advance (to avoid going out of business…) This means when you show up at 2:30 on a Friday afternoon they might not be able to start working on your parts for 2 weeks!
How many do you need?
Do you need 1, 10, or 10,000 parts? It makes a difference. Do you need them all at once or on some schedule. You need to give the machine shop as much information about this as you can at the beginning it will impact how they plan the production and the design of fixtures.
Young engineers in industry are commonly referred to as “Kids With CAD.” Because you can truly make that CAD software sing. With blends, fillets, flat bottomed holes, under cuts, deep grooves, flat bottomed tapped holes with threads to the bottom… the list goes on and on , and hey, sometimes you need those features to meet your design requirements. The thing is some of the more complex the features on your part are, the more features on your part, the more sides of your part with features, the more complex the set up will be and the longer it will take to make the part.
Tooling and Materials
If the machine shop you go to doesn’t have the tools or materials on hand to make you parts then they will need to be ordered. That process can take as little as a day and as long as two or three weeks depending on what is needed.
But I need the parts right now!
<< Watch this space>>
When you need your parts definitely has an impact on how long it takes to make them but only if the decision makers want to do you a favor. Your job at this point is to make them want to help if they can. Remember, if you need your parts As Soon As Possible, it is likely to be your fault, not the machinist’s. Remember that when you talk to them. It’s also good for you to know that ASAP can have any meaning between – all other work stops or is put on hold until your project is complete – and – we will work on your project as soon as we get to it.
My next post in this series will give you some tips and tricks for getting your parts quicker, when you really do need them ASAP.