In the last article, I argued that the goal of the drafting department is to get products produced (or installed, depending on your company) as opposed to many common misconceptions such as:
- “to do drafting (again I love your sarcastic personality)”
- “to create the best drawings possible”
- “to save the shop time”
- “to figure out what everybody else needs to do”
- “to save PM’s time”
From that argument it follows that decisions about how to structure your drafting department (including its rules and methods of drafting) should be made toward the purpose of getting product produced.
I shamelessly stole the above argument from Eli Goldratt, author of the book The Goal. If you haven’t read it, you should. I have held book clubs with my teams (engineers, project managers, estimators, shop floor, everybody should read this) and cannot speak highly enough of it.
Bottlenecks
I plan to steal (but adapt!) another argument from The Goal– in any sequence of dependent steps, there is one AND ONLY ONE structural bottleneck. This would be the step in the sequence that has the least capacity, and it will control the output of the total system. In other words, the maximum theoretical capacity of any system is that of its bottleneck.
My go-to example for this concept in our industry is this: imagine you have a millwork shop that has the following capacities:
- Drafting can draw 100 cabinets in a day.
- <Other office activities that we will omit because we are focused on production now>
- Engineering can program 40 cabinets in a day.
- Cutting centers that can cut 50 cabinets in a day.
- Edge bander that can band 100 cabinets in a day.
- Assembly that can assembly 30 cabinets in a day.
In this example, you will not produce more than 30 cabinets in a day. I’m using cabinets here just for a convenient measure of throughput; in a job shop our capacity is hours, not products (the number of products per hour will vary with complexity).
The Goal teaches that because of the above, improvements to non-bottlenecks are illusory. If I go to AWFS this year and purchase the world’s fastest edge bander which can band 500 cabinets in a day, I will not ship any additional products. I will simply pile up parts in front of the assembly department faster.
Another lesson is that the structural bottleneck should be protected at all costs. Every minute it is not working is a minute of lost production that can never be made up. Let’s use a notable example I see all the time- light valence. In many shops, their edge bander cannot band a 2” wide piece of light valence, so they cut it 4-1/8” wide, band both long edges, then make their assembly team stop building to cut it apart.
In our scenario the edge bander has much more capacity than the assembly department, so asking the edge banding operator to do “extra” work and cut the light valence apart (or run it through taped to a sled) will not reduce the overall output of the system. Having the assembly area no longer do that work will increase the overall output of the system. The edge banding operator will scream about the “inefficiency” involved.
Is drafting a bottleneck?
Now- back to drafting. Many companies believe drafting (or production engineering) is their structural bottleneck- often incorrectly. Many are overloading it with lumpy demand; you can overload any step by dumping enough work on it, but that doesn’t make it the structural bottleneck. I will discuss in later articles how project management causes this overloading, but the reason why this is incorrectly assessed as a bottleneck at the drafting department is because it is the first place you can see the work pile up. Before that it exists in a metaphysical form as “backlog.” It is hard to see a PM not turning over needed correction work, but easy to see a drafter who can’t get needed work completed for several weeks. Attacking this problem is the purpose of INNERGY’s bottleneck report, making this type of inventory visible.
Some companies REALLY DO have a bottleneck in drafting. Remember the light valence example above? The lesson was that a real bottleneck should be protected at all costs. Ask yourself: if your company has a bottleneck in drafting, does it act like it does?
Dumb rules
Many companies who claim a drafting bottleneck also drown the department in “dumb rules.” Every time something ever went wrong, they added a new rule to make sure it never happened again. In actual cases I have witnessed the trade-off ends up like this: they will avoid the once-in-five-years-expensive error in exchange for less productivity all day/every day/for those five years. This is not a savings.
Some other “dumb rule” examples I have routinely encountered:
- A bunch of dimensions or notes that the architect/GC/other trades don’t care about “just in case” the shop decides they want them. Remember, the parts here are being cut by machine and the drawings are to scale.
- Putting grain direction or material callouts on every single door and drawer. A single statement up front that “all doors are vertical grain” is good enough. Sure, once every year or two somebody will re-make a door and make a mistake, but you’ve removed TONS of effort. Note: if it can be automated then the analysis changes, but I see company after company placing manual CAD.
- Review steps- I am all for an internal engineering review, but should I put in place a single person to check all drawings? You have just guaranteed a new bottleneck. If you instead make sure your drafters learn from their mistakes (by ensuring a feedback cycle from the PM/shop floor to the drafter), then after a short painful period you’ll teach everyone what this one reviewer knew. I would rather have a system that delivers usable results 95% of the time than one which delivers 100% correct results in twice as much time.
Some of those “dumb rules” will be about aesthetics- “we need the best drawings.” But going back to the first article, we are here to make money; the goal of the organization isn’t “the best drawings.” We need drawings that are exactly good enough to get approved by the customer, get through production with minimal problems, get installed with minimal problems, and no better. It is extremely difficult to hit that target, so we should aim for a little better than that. If we have a system that can automatically draw a box around adjustable shelves but we do it manually because the automatic system draws at a different line weight than we’d prefer, you’re trading off productivity for something that doesn’t matter. No customer will stop using you because the line weight of your adjustable shelf annotations doesn’t match the wall.
Great, what do I do with all this?
If drafting IS the bottleneck, then protect it! Protecting it means assuring quality going in (never have a bottleneck working on something that can’t be used!) and adjusting processes to take work out of the department.
If drafting ISN’T the bottleneck, then something else is and that something else needs to be protected. This might mean asking drafting to do things that are “inefficient.” Remember the edge banding operator above being asked to cut the light valence? It was inefficient for him/her too. Paradoxically, some activities that are inefficient for a particular department are more efficient for the company.
Some examples of this class of decisions (optimizing drafting when it is not a bottleneck):
- Methods of construction/details/material selections that are made because they are easy for the drafter given the software/library they already have in place. They add extra cost or (even worse!) labor.
- Drafting choices which “feel good” as a drafter. A real life example I’ve run into numerous times is a drafter who drew a single product which has some open sections with exposed interiors and other closed sections with semi-concealed interiors. They will draw the open sections with wood veneer and the closed sections with melamine, so on a single board you need multiple finished surfaces. I 100% understand why this “feels good,” but it’s the wrong choice for most companies.
- “One Project = One Drafter”. That single drafter will take 6 weeks to draw the project, but that drafter will be very efficient since he/she is extremely intimate with the project. As an alternative to this approach, using One Piece Flow methodology I have put in place drafting departments that routinely had 15+ drafters working simultaneously on the same project. There are tools and methods you can employ to overcome the obstacles of this approach, but I could turn around a million dollar project in < 2 weeks this way.
- Refusal to move to more urgent work as it comes up. Switching contexts from one project to another has a cost in efficiency- for sure. If the shop is waiting on production work that is held up by a drafter who is working on completing drawings that aren’t needed for 3 months, then that drafter is being efficient for his/her department while causing inefficiency for the company as a whole.
What should you do if you find yourself in one of the drowning or drafting-centric-but-not-a-bottleneck departments? I mentioned the book club above which is a wonderful use of time. Challenge the rules. Stop complying with each rule and see who yells. If nobody yells, then nobody cares. If somebody yells, figure out whether they just don’t like change or whether there’s some good reason for what they want.
Too Long, Didn’t Read
TLDR: Use bottleneck analysis to maximize the throughput of your entire company (and therefore money made). Figure out if drafting is a bottleneck
If it isn’t a bottleneck: your attention would be better spent on earlier steps to level out the work going into drafting or on those activities that drafting can take on to pull work from the bottleneck.
If it is a bottleneck, TREAT IT LIKE ONE and protect it from stupid rules/processes, because they reduce the overall manufacturing output.
About the Author
Jonah Coleman has worked in woodworking for 15 years, during which he has built cabinets/custom items, managed projects, estimated, engineered, managed multiple engineering departments, managed teams of Project Managers, been an Operations Manager, written an ERP software used by 20+ shops, been named Time Person of the Year 2006 (check if you don’t believe it), written custom code for engineering software used by hundreds of shops, been repeatedly told that he is the only one who can prevent forest fires (both an honor AND a burden), and now works for INNERGY.
INNERGY is the ERP software written by woodworkers, for woodworkers. We have helped our 200+ customer firms become highly profitable. Our next goal is to revolutionize the practice of millwork engineering. Please join us at AWFS this year to see an exciting new set of features aimed at this goal.