The idea behind continuous improvement is that making lots of small advances will, over a long period, lead to significant productivity gains. Manufacturers able to sustain a commitment to this kind of incremental improvement see increases in efficiency, reductions in waste and even lower injury and accident rates.
One of the most powerful tools for finding and making improvements in manual processes is the time and motion study. This blog explores what it takes to perform a time and motion study in the manufacturing industry. Covering preparation, the study, data analysis and implementation of improvements, it guides the reader through putting this tool to work.
What is a time and motion study?
A time and motion study is a systematic analysis of a repetitive human task. To be precise, it’s a combination of a time study and a motion study. A time study of a manufacturing process determines how long a job will take. A motion study identifies all the movements the worker makes while carrying out a particular task.
A time study may be undertaken to set a standard time for a job, which supports production planning and control activities, or it can have a goal of finding ways of making improvements.
The standard time is how long it should take a proficient operator to perform a job repeatedly. It assumes working hard, but without straining or rushing and includes allowances for rest. The standard time is used to determine capacity and manpower requirements and to schedule work through the workstation.
When undertaken for productivity improvement, a time study identifies how long each element of a task takes. This data is then analyzed to find ways of eliminating, combining or speeding up each element.
A motion study is similar to a productivity time study. The intention is to find movements that can be eliminated, combined or sped up. This is usually so the job can be done faster but it may also be to find ways of addressing movements with potential health risks, such as bending, twisting and lifting.
Preparation for a time and motion study
Start by selecting a process or operation. The main considerations are:
- Does a problem or clear opportunity exist? Bottleneck operations are prime candidates, as any time saved here benefits the whole production system.
- Is a standard time available for production planning and control?
- Are there concerns about repetitive or potentially unsafe motions?
- Where the task is straightforward but repetitive, it may make a good training or practice study.
Define the expectations and goals for the study. Is it to set a standard time, to find and implement improvements or to address potential health risks?
Finally, review any prior studies and gather the equipment needed. Prior studies can indicate specific issues or challenges to look out or to check for resolution. For example, a previous study may have observed filing or trimming work because a mold tool was in poor condition. If the tool has been repaired or the machine replaced, this should not be observed.
Regarding equipment, traditionally, a production time study needs nothing more than a clipboard and a stopwatch. Today, this might be supplemented by one or more cameras, preferably tripod mounted. In addition, specialized video analysis software may be helpful for post-study review.
Conducting the study
If more than one person performs the operation being studied, the first step is to select a study subject. This should be done in cooperation with the local supervisor. The ideal subject is one who is experienced at the job, but has not been doing it so long the motions have become automatic.
At the agreed date and time, the study starts with the observer creating a list of all the task elements. For example:
- Lift from tote and place in fixture
- Pick screw from bin and position at location #1
- Pull down screwdriver and fasten screw
(This is where reviewing prior studies can save time.) A common mistake is defining elements that are too small to time accurately. Less common is making the elements so big they don’t provide enough detail for improvement idea generation.
Then, as the study subject goes through the task, the observer logs the time taken for each element and the rate at which the subject is working. Timing requires a stopwatch with a lap function. Rating performance is a skilled task that needs experience and training. Usually, a skilled operator will be working at 100%, but nerves (most people find being watched is stressful), may cause them to work faster or slower.
The observer should record as many cycles as possible so the times for each element can be averaged. Robustness may be further improved by repeating the study with additional subjects. This takes more time, but will raise confidence in the results obtained.
Data analysis
Analysis is easier if the operation was recorded on video as this can be replayed. Analytics software can make it easier still by providing timing between individual touch points. However, with or without video, the steps are:
- Average the data
- Determine how long each element would take to perform at 100% effort
- Apply appropriate allowances
- Calculate the standard time
- Compare with data from other sites and/or previous studies
- Identify improvement opportunities
Implementing improvements
Having identified ways in which the time for the job can be reduced (and perhaps the amount of movement needed to complete it), the hard work of making changes begins.
Start by formulating an action plan. This should cover responsibilities, costs and timescales. Items in the plan could include actions such as designing a new workbench, having it made and setting it in place, or creating new fixtures or buying new tools.
Some improvements may only be changes in working methods. These require training along with drafting of updated Standard Operating Procedures. Improvements of a more physical nature, such as a new layout or new tools, need an implementation date and training to support their use.
After implementation, it’s important to check the new methods are being followed and new equipment and layouts used as expected. If deviations are found, find out what was wrong with the proposed improvements and make changes accordingly.
Only when the new methods have been used for an extended period should a new time and motion study be conducted. This is because it’s important to let workers become comfortable with the new ways of working.
Benefits of a time and motion study
A well-planned and professionally conducted study yields a host of benefits, providing improvements are implemented, reviewed and adjusted as needed. Those benefits include:
- Increased manufacturing efficiency: By identifying wasteful movements and non-productive use of time, unnecessary steps are reduced and workflows streamlined.
- Higher productivity: Standard times provide insights into ways of optimizing labor and machinery usage, leading to higher output and better resource utilization.
- Cost reduction: Enables elimination of redundant processes (for example, double handling, stacking or packing) and improves overall efficiency.
- Better quality: Increases consistency between operators as the new or improved methods are rolled out and reduces variability at each workstation, leading to higher quality and fewer defects.
- Improved employee utilization: With realistic standard times it’s feasible to optimize task assignments and workload distribution, ensuring employees are used effectively.
- Informed decision-making: Provides data-driven insights that assist management in making strategic decisions regarding process improvements and investments.
- Standardization: Supports development of SOPs.
- Greater competitive advantage: Improves overall operational efficiency, leading to shorter production times and increased responsiveness to market demands.
Improve manufacturing efficiency by addressing waste and nonproductive time
Continuous improvement requires attention to every aspect of manufacturing, including how repetitive manual tasks are performed. Time and motion studies are important for analyzing these tasks in fine detail and identifying improvement opportunities. This blog has provided guidance on preparing and conducting such studies and identified benefits such as higher productivity and efficiency.
Another important aspect of continuous improvement is to eliminate unplanned downtime and all its knock-on effects on output. As a leader in outsourced industrial maintenance, ATS helps manufacturers address their downtime problems and improve operational efficiency. Contact us to learn how we could help you.
