Evaluating an MTM-UAS Time Study in Workplace Planner
It is common to move tasks from one operator or workplace to another when performing an assembly line balancing study in Assembly Planner. If activity times were defined using a predetermined time study tool such as MTM-UAS, then it is likely that the operator walk times will be inaccurate as the collection and sequence of tasks assigned to an operator after line balancing will not match those assigned initially.
To ensure that the operation times are below the line TAKT, engineers need to evaluate the layout of their moving assembly line workplaces prior to implementing those workplace designs on the shop floor. This evaluation must be conducted by combining the MTM-UAS elemental task analysis with an AutoCAD layout proposal, generated by facilities engineering.
The desired result is an optimal layout confirmed via a detailed operator walk path flow diagram, updated MTM-UAS elemental task description, validation of the completion of the tasks within the allotted TAKT/cycle time, and an animation for engineering and supervisory visual cycle validation.
It is desired that the process analysis be conducted at the MTM-UAS elemental level to ensure that modifications to the operator process sequence can be made and validated/recorded by Industrial Engineering.
Likewise, it is desired that the layout evaluation, modification and animation, be conducted within the AutoCAD layout drawing, to minimize the need to re-model and subsequently update the layout as an additional step.
An integrated solution between Proplanner’s Assembly Planner and Workplace Planner (WPP) applications provides a robust analysis, visual flow diagram, detailed reporting, and moving line animation within 15 minutes of CAD time, from the time that the input MTM-UAS level, elemental operator routing file is generated.
This analysis method requires no time/expertise intensive process model building, and yet provides for a superior result in about 1/8 the time of competitive techniques (approx 2 hours), and has the added benefit of being AutoCAD based, which eliminates the additional step of updating the CAD layout to support the desired analytical result.
The process starts with an MTM-UAS operator-level time study as shown below. This report is a text file extract from the Industrial Engineering time estimation system.
From the spreadsheet oriented CSV file shown previously, a WPP file is manually formatted in MS Excel by the engineer in about 5 minutes.
For a workplace where the product remains stationary while it is worked on, locations can be defined as simple text labels describing the location on the vehicle or in the workplace where parts and tools are referenced. If the product is moving through the workstation while work is performed, then locations on the product can be defined using a relative (to the part) coordinate system and are prefixed by the ‘@’ symbol.
The following diagram shows one of the two grid approaches available. In this approach, the vehicle is divided laterally as “L”eft, “R”ight, and “C”enter and then longitudinally with “A” at the front and then down to some user-defined letter (“D” in the case below) at the end.
The time to perform this task depends a lot on how much the engineer knows about the process and the number of elemental routing lines that need to be updated. A one to three minute cycle time could take 10 to 30 minutes to define the locations for. Ideally in the future, the Industrial Engineer who created the MTM-UAS time study would also specify these part and station locations in their time study descriptions for future automated reference.
The example workplace planner study spreadsheet file shown below uses the other relative addressing approach, where the vehicle is longitudinally defined numerically, as opposed to alphabetically, from 1 to “n”.
Finally, the engineer needs to validate that the default properties for the operator walkpath colors, walk speeds, starting locations and part travel speeds are correct.
In addition, the engineer needs to specify a line down the center of the workstation(s) for the parts to travel. This task can take from 1 to 5 minutes, depending on the number of changes required, and the number of operators and workstations being studied. The user interface for those tasks is shown below.
Workplace Planner automatically calculates operator intersection locations on the moving part as it travels through the workplace. WPP then automatically generates the walkpath for each operator and computes the walk distances and times accordingly, as show below.
Workplace Planner generates a summary analysis for each operator:
It also generates a LEAN process Chart for each operator. In these two examples, the following table of XYZ LEAN parameters is automatically converted to default WPP values.
And finally, a detailed process report by element is generated by WPP.
In summary, Workplace Planner allows the engineer to quickly and accurately convert their predetermined time studies into detailed layout-specific workplace models that validate cycle times and conform to modern LEAN evaluation documentation.
Join our mailing list to be informed of the newest blog posts.