Knowing the Ideal Manufacturing Cycle Time
By Ben Hershey, CEO, The 4Ward Group of Companies
Building components is really great! It was a lot of fun in the 1970s when several plants had competitions on who could build the fastest run of trusses (for example, see Joe Kannapell’s article on Vertical Presses–The World Record). Back then, it was really easy to calculate cycle time, because we had very similar trusses and very long runs. Enter the 1990s and, WOW, did that change fast, as we quickly began building more and more complicated roof and floor systems. Today, our team hears a common theme from manufacturers: how do I know what the ideal cycle time is when I have 125 different sample components or processes with varying times ranging from 20 seconds to 20 minutes. Think on that for a moment.
Often within the 4Ward team, we will have a spirited debate about the capacity or expected cycle times of a given operation. Because all 8 of us have similar but diverse backgrounds, we can have different perspectives on what the exact capacity will be, but our approaches and how we calculate the cycle time to reach capacity are very similar. Carl Allison, Keith Dewing, and I have very similar backgrounds of originally coming up off the production floor, so we have a common approach. Owen Eldridge and Shane Soule have a similar approach given their similar backgrounds from operations. And, while Roger Wagner, Joe Butler, and Dylan Thomas have different backgrounds, they share our perspectives from their own experiences. Because of this, we may approach capacity from slightly different directions, but we arrive at the same conclusions because we understand and correctly calculate cycle time. Although many within the manufacturing sector claim to know how to calculate cycle time, simply having an equation is no guarantee. The key is having the right variables.
So, let’s break it down.Here’s a good definition:
Manufacturing Cycle Time isthe time of actual production from when a customer order is released to the plant floor for a particular product through to the completion of all manufacturing, assembly, and testing for that specific product. (It does not include front-end order-entry time or engineering time spent on customized configuration of nonstandard items, or time in finished goods inventory.)
Remember when calculating cycle time, the formula is:
Manufacturing Cycle Time = Process Time + Move Time + Inspection Time + Queue Time
In some cases, you may also include the Wait Time, which would be the Delivery Cycle Time
An example of this might be, if I were looking at the cycle time at the component saw (yes, many plants still use them) for a batch of work:
Process Time: 12.25 minutes
Inspection Time: 2.18 minutes
Queue Time: 5.41 minutes
Move Time: 4.51 minutes
Total Cycle Time: 24.35 minutes
But, in the cycle time, are you really digging in to see what actually makes up the basis for each part of the process? Looking at those details will show you how you can improve the cycle time.
What Not to Do When Calculating Cycle Time
Do not use averages to derive “an ideal cycle time.” You might as well stick your head in the sand if you are going to use that approach. When you have a range of cycle times from 20 seconds to 20 minutes, you need to have the ability to know how machines/process are capacity-constrained, so you can accurately schedule machine/process time that delivers great on-time delivery to the next step in the process.
Do not tie productivity measurements to just a machine cycle time. Other things often affect cycle times, such as having operators in training or issues with maintenance, scheduling, raw materials, quality, and more. The better metric to use is OEE (overall equipment effectiveness), which takes the variables into consideration and highlights the cause of any shortfalls or over-accomplishments. Resources can be directed at the root cause of process problems that make the “ideal cycle time” impossible to deliver until corrective actions are taken.
What Should You Do When Calculating Cycle Time
1. Use a Value Stream Map. The objective is to understand the capacity necessary to make each product type based on customer demand in a predetermined time frame. You can define both the capacity burden and the flow by doing a VSM. The goal is simply to balance your lines around the appropriate constraint to optimize throughput. You want to eliminate WIP that is stacked up in excess; think of all the carts loaded with cut parts waiting to be built in front of the gantry. You want to balance workflow, the line, i.e., the necessary support equipment, to complete the product.
2. Be data driven and use the Pareto principle (80-20 rule). This allows you to identify and focus on the best opportunities first to improve the business. Use cross-functional teams–and pull in other resources as required to address opportunities. Move quickly with a keen sense of purpose. We have an abundance of data in our operations we need to use to our advantage.
3. Train up your team. There is so much to be gained by continual training, for example, on the Theory of Constraints or VSM. Be proactive with employee education and training, or you will struggle to make the profound impact that should result. Once knowledgeable employees engage, they’ll understand why being alert for new constraints presents opportunities for ongoing improvements.
4. Cross Train Machine Operators. There are a number of times I am sure you have seen a linear saw not being operated because the only operator of that saw is not at work that day; this causes a constraint. When an operator calls in sick, the constraint still needs to be run. Make a priority to cross train all operators to run multiple machines used in their area to always ensure coverage and provide a steady flow of work-in-process, that will ensure a steady supply to alleviate all constraints.
In summary, it’s relatively easy to get a good read on where cycle time improvements will immediately, and positively, impact the business. Over time, you continue to improve cycle times on the constraint until the constraint moves to a different machine, and then your efforts go to work on moving the new constraint. Again, and again. This is what we mean when we talk about continuous improvement!
Best Practice Tip
One of our customers asked the other day about resources for providing lunch and learn seminars for local architects— Great Question! SBCA has an awesome library of resources that members can use to provide Component Technology Workshops in their market place. Want to conduct a tour of your component operation, or make a presentation, or even provide a webinar, there are great resources available. If you have not tried this yet, contact the SBCA Staff or check out the website. You won’t regret it!
Ben Hershey is CEO of the 4Ward Group of Companies including Consulting Solutions, Labor Solutions, Offsite Solutions, Design Solutions and Accounting Solutions. When the industry needs an actual expert, they turn to 4Ward team with more than 150 years of experience. 4Ward Consulting Group isthe leading provider of Management and Manufacturing Consulting to the Structural Component and Lumber Industry. A Past President of SBCA, Ben has owned and managed several manufacturing and distribution companies and is Six Sigma Black Belt Certified. Ben has provided consulting to hundreds of Component Manufacturers, Lumber Dealers, and Millwork Operations in the past seven years. You can reach Ben at ben@4WardConsult.com or 623-512-6770.
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