Wednesday, December 7, 2022
Sunday, December 4, 2022
All companies have processes, how a company pays it's supply chain, and how it gets paid by it's customers are two big processes that need to go right. There are many different processes, but today I'm just going to talk about one, the drawing review.
As I was thinking about this post, I had the thought that there are probably two general types of companies. Those that have A similar number of inputs and outputs, like a farmer who buys five tons of seed, and half a year later has 500 tons of corn to sell, essentially one input and one output. Obviously modern farming is ridiculously more complicated than that, for example with satellites guiding tractors to make the most use of a field, and whole ecosystem of companies and products designed to make sure those seeds are planted on the perfect day at the perfect depth for their soil, with the perfect fertilizer. Similarly the services industry, while there may be a lot of specialized tools in any given service job, essentially the basic trade is one person's time for the other person's need. The other type of business, where I am far more familiar is where hundreds or thousands of individual parts are put together in order to be sold as a single working thing to a customer. In other words, a huge number of inputs and a small number of outputs, like the automotive industry, where thousands of parts go into a vehicle, and at the end you have three different trim levels, and seven colors, and four wheels to pick from, and that's it.
A big part of making these complex things like cars, is designing one individual part, making a drawing also known as a blueprint, and having either an external or internal manufacturing group make the part. A drawing is one of the main deliverables from a design engineer. It is essentially, how to inspect the part so that it performs according to it's performance requirements. There is a push to put all of that information into the CAD (computer aided drawing) file, however it's a slow transition, so for the foreseeable future, drawings will continue to exist at most companies as the source of truth for what the physical part should be.
Drawings generally come in two flavors, in work (or draft) and released. There are different softwares to handle the approval process to go from an in work drawing to a released one. In most cases though, there is a human that did not design the part, that will review the drawing, often several humans. It is a way to catch errors, typos, and other things that could result in a nonfunctional part when it gets made. Often there are checklists for drawing reviews, other times it's left totally up to the discretion of the reviewer what he or she checks. Some people look at these as a chance to catch all the wrong things on a drawing, but as I've gotten older, I view them more as a language to communicate a desired function to the person manufacturing the part. Which is to say, most of my comments on drawing reviews these days are suggestions rather than requirements.
The drawing review is often one of the last steps in the larger design review or design release process. The process that companies use to design an assembly of many different parts, and then release that to manufacturing for it to be made. It can be used as a stop gap, meaning, design reviews run the gamut from every dimension being discussed, to a few slides showing how the product generally works, yet the drawing review can often catch items that would make manufacturing the part impossible, items were not caught in a design review.
There is no right or wrong for how to do a drawing review. It will be a different calculation for each company of what level of rigor or autonomy they want reviewing drawings. When I made my ultralight ice axe for Kickstarter, I actually made the conscious decision not to make a drawing, and accept any reasonable ice axe from the manufacturer. That is one extreme, since that part does not have to interact with any other parts. However, for assemblies of many parts, getting all of them to come together nicely can be very difficult, and it starts with good drawings.
Will I write more about company processes? I don't know, but if I do, here is a list that I might write about.
- How to pay vendors.
- How to be paid by customers.
- How to make or do a thing (work instructions).
- How to document an imperfection or nonconformance.
- How to approve a purchase.
- The Design Review
- Meeting a requirement, and what is a requirement?
- How a company validates it's product before selling it.