When it comes to printed circuit boards, line efficiency is the ratio of the number of hours a pick-and-place machine positions parts on the PCB divided by the quantity of hours the SMT assembly lines are staffed. There are different ways to measure line efficiency, including capacity utilization, which is calculated by comparing the production to an average level of acceptable production and line efficiency.
Understanding line efficiency is very important for manufacturers and assemblers of printed circuit boards. The faster a manufacturer can churn out fully-assembled printed circuit boards that work as intended, the more money that manufacturer of PCBs can make. If a PCB manufacturer/assembler is systematically losing efficiency and underproducing, identifying and rooting out the problem must be done quickly to avoid business failure.
Line Efficiency Formula
When calculating line efficiency, deciding to use the SMT line efficiency or production line efficiency calculation must be determined. Many experts consider SMT line efficiency to be a more robust measurement.
The line efficiency formula is the number of hours when a high-volume pick-and-place machine is putting parts on the printed circuit board, divided by the number of hours where you are staffing the SMT assembly line. Put more simply, it is the placement time hours divided by the staffed time hours times 100. This number gives a simple, clear measurement of performance.
The reason many managers are reluctant to use production line efficiency as a measure instead of SMT line efficiency is its failure to take duration into consideration. We base the ratio on actual staffed time, rather than optimum time, and do not take the use of labor into consideration. It is important to note that productivity is affected by outside forces that are difficult for the assembly manager to control. Market demand determines the printed circuit assembly volume required of a factory.
Placement time and SMT time are also fairly easy to calculate, so coming up with a line efficiency number is often a quick and painless process. The controller of the pick-and-place machine should have a complete recording of when the machines are placing parts and when they are not, so a simple consult of these records identifies placement time.
Staffing hours will be easy to calculate if there is someone in charge of keeping organized, computerized records of staff time. Remember that even if employees are allowed breaks on company time, those breaks count as staffed hours. To maximize line efficiency, breaks, meals and meetings should be staggered so workers are on the line at all times during staff hours.
The result of this way of calculating provides a clear and honest line efficiency measure that is consistent. There is no room or mechanism for deception, so there will be no doubt whether or not changes need to be made and no doubt whether or not those changes are having an effect.
While SMT line efficiency measuring is an effective way to assess productivity, it is a good idea to have other productivity measures in place as a check on this measure.
How to Improve Line Efficiency
What are some good ideas for line efficiency improvement? While collecting data is very important, just as important is what is done with that data. In addition to calculating line efficiency, identifying the factors affecting that line efficiency allows them to be analyzed as well as analyze team performance.
A quality analysis of the data that is collected will make the reasons that productivity may be lagging very clear and should guide changes implemented to improve that efficiency. Possible reasons for lagging productivity may be that:
- There are not enough people on the line.
- There are too many people on the line.
- The machines used to place components are old, out-of-date or not functioning optimally.
- There is poor line configuration.
- There are time management issues to address.
Millennium Circuits Limited is an experienced supplier of printed circuit boards for a variety of applications. We have connections with assemblers and understand the many pitfalls that can arise, as well as what it takes to provide you with a quality PCB product, even at high volumes. For more information or for a quote on quality printed circuit boards, contact MCL today.