Predetermined motion time system (PMTS) is a method of arriving Standard time of a work, that comprises predetermined time values corresponding to each and every work element.
When we talk about Industrial engineering, work measurement plays a crucial role for measuring productivity and reducing operational costs. As we already have traditional ways of doing time study which are widely used, Predetermined Motion Time Systems (PMTS) is known for its speed of doing, accuracy and consistency in measurement of work and its time.
Understanding the need of PMTS while we have traditional methods
Okay let me take you into a real example which will help you understand why PMTS stand out from other Methods.
You are walking through a production floor, where you can clearly see operator are focused, tasks are getting done, machines works efficiently but something feels not right. You ask the supervisor, “How we know if everything is efficiently working?” He replies, “Our engineer did a time study a few months ago…. Used a stopwatch and rated the operator performance and that’s how we calculate the standard time.”
And here the thing is: Subjectivity.
One operator’s 100% performance rating might be another’s 90 % and within the month lot of scenarios will get change and it will be not possible to do detailed stopwatch study every time.
All in all, here are the limitations traditional time study (Stopwatch, Method- time measurement).
- Performance Rating: Subjective and person dependent.
- Time-Consuming: Detailed elemental breakdown can be slow and time-consuming activity.
- Inconsistency: As performance rating depends on working speed/ age factor an experienced engineer can only get the rating correctly, so the results may vary from person to person.
This means the standard time we set today might be challenged tomorrow, depending upon engineer (who is taking the observations).
That’s where Predetermined Motion Time Systems (PMTS) comes in.
PMTS does not consider the guess working in deciding how fast or slow person’s movement, it focuses on the task itself.
What is Predetermined Motion Time Systems (PMTS)?
Predetermined motion time system (PMTS) is a method of arriving Standard time of a work, that comprises predetermined time values corresponding to each and every work element.
Basically, by answering questions like: What kind of movement involved? How far does the person move? Is there any tool that is controlled by person? We can find out the time for doing that activity.
Let’s learn through an example
In a factory setting, imagine a worker who is assigned the task of installing light switches onto a plastic panel. This is part of an assembly line which makes an electronics product. The task seems simple, but if we observe closely, it’s made up of several small, repeatable motions that can be studied and timed in advance. That’s exactly where predetermined motion time systems come into play.
The worker begins by moving their hand toward a tray that holds light switches. This movement is commonly referred to as a reach motion. It’s a short action, involving only the arm and a quick glance to locate the part. Once the hand is over the tray, the fingers close around a switch. This is the grasp motion. It involves precise control since the switch is a small component, and it must be picked up securely without slipping.
Next, the hand travels from the tray to the assembly panel fixed in front of the worker. This is considered a move motion. The switch is being carried during this motion, and since it’s light and the path is unobstructed, the movement is smooth and quick. When the switch reaches the panel, the worker must align it carefully over a small rectangular slot. This positioning requires visual accuracy and some minor wrist adjustments, especially if the slot is slightly rotated or tight-fitting.
Once aligned, the switch is pushed down into the slot until it clicks into place. This pressing action involves applying moderate finger force, which is another standard type of motion in PMTS. After the switch is locked in place, the worker returns their hand to the starting position to begin the next cycle.
In a predetermined motion time system, each of these motions—reaching, grasping, moving, positioning, pressing, and returning—is assigned a standard time based on earlier studies. These times are added together to calculate how long the entire task should take under normal working conditions.
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very good information