Andritz Inc. Ergonomic Analysis

Overview

Andritz is a large worldwide company that specializes in creating systems, equipment, and services for the paper, pulp, and hydro power markets. The Muncy, PA plant specializes in making steel refiner plate castings. The senior design team at Penn State spent 14 weeks analyzing two features of Andritz’s plant: the mold line pattern change and gate removal process.
The objectives for the project are to help Andritz Inc with safety ergonomic improvements during the gate removal and during the pattern change of the mold line process. The ergonomic issues at the gate removal occur when the operators are tasked with removing the gates of the heavy castings which results in two parts, the gate and the plate. After the gates are removed, the operator throws them in bins. The resulting refiner plate is carried by the operator to the according racks.
The ergonomic concern at the mold line process occurs when the operators are switching out the heavy pattern plates. The operators are tasked with placing the patterns into the mold line which involves an awkward grip on the pattern. This adds additional and preventable strain to the back and arm when having to make these rapid pattern changes at the mold line. Possible worker-friendly solutions were analyzed and presented.
Measurements were taken and ideas on how to reduce Andritz’s problems were developed. All ideas and concepts were openly discussed with the Andritz Inc. team to get their opinion to see if the solutions are plausible in their workspace. A series of NIOSH, The National Institute for Occupational Safety and Health, lifting models were used to determine the main factors of strain to the operators’ bodies. The NIOSH equation uses a series of multipliers based off measurements of a given process to determine the maximum amount of weight the operator should be lifting. A NOISH and lifting index was formulated for both the pattern change and gate removal.
The NIOSH multipliers and values of the measurements helped to visualize what needs to be reduced in order to decrease the lifting index. The mold line as well as the gate removal NIOSH equation showed that the horizontal location of the castings and patterns relative to the body was the leading cause of strain.

Objectives

Reduce strain on the body that is caused by the process of casting’s pattern changing in the moldine. Reduce strain and possible injuries that are caused in the process of hammering the gates of the castings. Calculate the strain the operators’ bodies undergo while completing each task, and how much strain is relieved when applying the new methods

Approach

The first step was to visit the site. Within the first weeks of the semester the team traveled to Muncy, PA to visualize the details of the Andritz facility. The Andritz team explained the current situation and described concerns for the team to analyze. After the visit, the team started brainstorming different solutions to reduce the strain of the operators. It was decided that the NIOSH lifting equations would provide Andritz a sufficient analysis of the mold line pattern change and gate removal.
The goals for these two processes were to reduce the strain the operators encountered, which would lead to safety improvements. The team conducted a series of NIOSH equations to determine and mitigate the ergonomic flaws. There are separate NIOSH equations for the pattern change and gate removal processes. As explained in Appendix A, the output NIOSH value is also known as the recommended weight lifted (RWL). The NIOSH equation takes into account several factors as shown in the diagram in Appendix A. The output value is the maximum weight that the operator should be lifting without increasing the risk for back pain. The NIOSH number was then plugged into the lifting index explained in Appendix B. The equation for the lifting index is the weight of the produce divided by the NIOSH constant. Since there are a range of weights, the maximum, minimum, and average weights were inputted into the lifting equation. If the lifting index is below one, this means the NIOSH conditions are efficient. However, if the lifting index is above one, the conditions are not optimal.

Outcomes

After analyzing the NIOSH RWL and lifting equations, recommended measurements were suggested that will reduce the lifting index as shown in the tables below. The variables of H and D were the best possible measurements to reduce. When they were decreased (within physically possible limits), the lift index was reduced below 1 for most cases.