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.
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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.
The advantage is that engineers don’t need to time each worker with a stopwatch. They can estimate the standard time before the job begins, plan workloads fairly, balance the assembly line, and even redesign the workstation if one motion takes more time than expected. For example, if the tray is placed closer, the reach motion becomes faster. If a new tool is introduced that helps align the switch instantly, the positioning time can be reduced.
This way, PMTS helps create realistic expectations, improve productivity, and maintain consistency across operations. It focuses on standardizing work without needing to rely on individual performance, and it does so by analyzing tasks in small motion elements and assigning each a reliable time estimate based on prior data.
Two important points in (PMTS)
Split Work into Elements
The entire task is broken down into basic motion elements such as reach, grasp, move, or press.
Assign Standard Time
Each element is assigned a standard time value based on motion study data and pre-established benchmarks.
How Are Standard Time Values Arrived At in PMTS?
Don’t confuse this with Standard time calculation of the tasks. We are taking about creating pre determined time data bases. In other words, the activity which should be done in prior and it requires deeper analysis and research.
Standard time values used in predetermined motion time systems are not randomly assigned. They are the result of detailed scientific studies carried out in controlled environments. Typically, trained workers perform basic motions such as reaching, grasping, or moving objects while being filmed or observed under standardized conditions.
These recorded motions are then analyzed frame-by-frame to understand how much time each motion takes on average. The data collected from a large number of observations is then statistically processed to determine consistent and reliable time values. These values are not based on how one person performs a task, but rather on a large sample of motions across various individuals to ensure fairness and accuracy.
Over time, this data forms a database of motion-time standards, which can then be referenced when analyzing new tasks—eliminating the need to use a stopwatch for every job. That’s how PMTS provides predefined time values for work elements, forming the basis for setting realistic and efficient standard times in manufacturing and service industries.
A bit more about Standard time Data base
In PMTS, assigning standard time is not as simple as picking a single fixed value for each motion. The time values for each basic motion—like grasping, reaching, or moving—are stored in a well-organized database. This database is built through extensive motion studies and includes a wide range of time values for different versions of the same motion. For example, a simple “grasp” motion might take different amounts of time depending on whether the object is large or small, easy or hard to hold, close to the body or far away, or even whether the worker uses one hand or two.
These variations are carefully cataloged in the PMTS database so that industrial engineers can choose the most appropriate time value based on the actual working condition. That’s why selecting the right motion category and the right time from the database is one of the most critical steps in applying PMTS accurately. If the wrong time value is used—even slightly—it can lead to unrealistic expectations, overburdened workers, or inefficiencies in line balancing.
Furthermore, the database often contains motion descriptions with conditions like “grasp with precision,” “grasp from bin,” or “grasp under obstruction,” each with its own time value. This level of detail ensures that PMTS isn’t just fast—it’s fair, consistent, and realistic. The reliability of the final standard time depends heavily on how well the analyst interprets the task and picks the corresponding motion elements from the database.
The Calculation
Practical Breakdown – Applying PMTS Concepts
This example demonstrates how a simple assembly task can be broken down into small motion elements. Each motion is then assigned a time value taken from a predetermined database. The values shown are for learning purposes only and do not reflect real-world standards.
| Step | Motion Type | Condition / Description | Time from predetermined database |
|---|---|---|---|
| 1 | Reach | Hand reaches to pick switch from tray (20 cm distance) | 0.30 sec |
| 2 | Grasp | Small part, easy to hold | 0.20 sec |
| 3 | Move | Carry to panel (30 cm, unobstructed path) | 0.35 sec |
| 4 | Position | Align switch precisely into a small slot | 0.60 sec |
| 5 | Press | Push down to snap into place (moderate force) | 0.30 sec |
| 6 | Return | Hand returns to initial position | 0.25 sec |
| Total Task Time | 2.00 seconds | ||
Note: The time values shown above are for illustrative purposes only and should not be considered industry standards. In real-world applications, the appropriate value must be carefully selected from the database based on the specific motion condition and environment.
Conclusion
PMTS is fast, consistent and objective and it’s not only a tool for time study, it’s a faster and smarter way to analyze activities without bias outcome, quickly measure complex tasks by breaking into standard elemental form, improve productivity, no need of relying on subjective rating.
We hope this article has helped you understand what PMTS is and how it works in practical, real-world settings. From breaking down a task into basic motion elements to assigning each one a specific time, the core idea is to bring structure, fairness, and consistency to how work is measured and managed.
The most challenging part of PMTS is not just the motion breakdown — it’s selecting the right time value for each element based on the exact task conditions. The accuracy of your final standard time heavily depends on how well you match the motion being performed to the correct reference in the database. Also the reliability of time database.
But don’t worry — you’re not alone in this process. There are well-established systems and tools developed by experts who have conducted in-depth research on standard motion times across a wide range of tasks. They have created global time data bases for all possible task elements. These services often come with structured databases, user-friendly interfaces, and logical decision flows that help you pick the most appropriate time value based on the situation — saving you both time and effort.
Whether you’re an industrial engineer, production planner, or operations analyst, PMTS gives you a scientific and scalable method to plan work smarter, not harder.
If you and your team is a well expert in time study and work analysis, you can also create standard time data bases for your factory operations. And use those data for arriving the time standards easily and quickly, for future requirements.
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very good information