肌肉骨骼潛在風險評估改善以鑄造業為例分析

隨著工業的蓬勃發展，為了滿足人們對消費品的需求，許多作業都以自動化的方式取代人力進行生產，以求更有效率地提升產能。不過，無論科技如何進步，在產品製造的過程中，仍無法避免需要使用人力來搬運物料，也就是所謂的「人工物料搬運(Manual Materials Handling , MMH)」。本研究目的在於尋找鑄造業加工製程中的改善方向，利用實驗室模擬現場加工的動作，來模擬場內某一個製程，找出較好的動作與工作配置，以有效防止下背痛與上肢肌肉痠痛等傷害。本研究設計一款手孔箱，於實驗室模擬不同手持位置的物料搬運狀況。以主觀知覺問卷、肌肉電位訊號放大器蒐集受試者在進行抬舉時肱二頭肌與後背部左右兩側豎脊肌肌群變化量主要目的在於改善鑄造業作業方式並提出相關建議與方法，現場觀察後發現該鑄造場目前的作業狀況為作業員在無擁有握持介面的容器輔助下直接將物料搬運至工作台進行加工，類似本研究模擬的手持於P3位置情形，藉由KIM-LHC檢核表以及肌肉電位訊號與生物力學法，分析抬舉作業時之風險因子評估，受試者配合手孔箱的不同手持位置與物料重量，將其搬運至模擬的工作台。探討物料抬舉時手持位置[兩側對稱手孔的上(P1)、中(P2)，與箱子底部無手孔的(P3)等3 種位置]、物料重量[4.5公斤(W1)、14公斤(W2)等 2 種重量]、有無戴手套[有(G1)、無 (G2)]等三項實驗因子對於受試者在知覺費力評量(RPE)、肌肉負荷程度(%MVC)[肱二頭肌與後背部左右兩側豎脊肌]與第五腰椎及第一薦椎 (L5/S1)受應力等三項依變項的影響，探討不同手持位置對於受試者作業時的主觀感受與生理變化量。研究結果發現手持位置、物料重量等因子對於知覺費力評量(RPE)、肌肉負荷程度 (%MVC)皆有顯著的影響，而有無戴手套對此兩者皆則無顯著影響。RPE在手持位置間以無手孔的 P3 最高，其次為有手孔的 P1最後為P2；RPE 在物料重量間，W2 顯著高於 W1。%MVC 在手持位置間以無手孔的 P3為最高，並以有手孔的 P1、P2 負荷較低；重量因子對於左豎脊肌的邊際影響最為顯著，其次則為右豎脊肌，而肱二頭肌被重量因子的影響最小。腰椎受力評估分析得出，手持於P3位置物料重量為W1時，腰椎(L5/S1)所承受壓應力值為最高3443.06NT，而手持於P2位置物料重量為W1時，腰椎(L5/S1)所承受壓應力值平均為最低3149.73NT有效降低作業員罹患下背痛發生的風險。透過實驗結果分析，當受試者抬舉兩側對稱手孔的(P2)位置有最好的心理與生理感受，透過KIM檢核表比較改善前後的差異，風險分數從32分的降至16分，為本研究中最佳的手持位置，不僅減少作業員過低的彎腰姿勢，還能有效防止下背痛與上肢肌肉痠痛等傷害。

關鍵字

人工物料搬運；職業性肌肉骨骼不適；重複性抬舉；握持介面

並列摘要

關鍵詞：人工物料搬運、職業性肌肉骨骼不適、重複性抬舉、握持介面 Abstract With the booming of industry, in order to meet the demand for consumer goods, many operations are automated to replace human production in order to increase production capacity more efficiently. However, no matter how advanced the technology is, there is still no way to avoid the use of human labor to move materials in the process of product manufacturing, which is called "Manual Materials Handling (MMH)". The purpose of this study is to find the improvement direction of the machining process in the foundry industry, and to simulate a certain process in the field by using the laboratory to simulate the machining motion, and to find the better motion and working configuration to effectively prevent the lower back pain and upper limb muscle soreness and other injuries. In this study, a hand-hole box was designed to simulate the material handling in different hand-held positions in the laboratory. A subjective perception questionnaire and a muscle potential signal amplifier were used to collect the changes in the biceps brachii and the left and right lateral erector spinae muscles in the back of the subject during lifting. In this study, the KIM-LHC checklist, muscle potential signal analysis and biomechanical method were used to analyze the risk factor assessment during lifting operation. Three experimental factors were investigated, including hand-holding position (P1, P2, and P3), weight (4.5 kg (W1), 14 kg (W2), and the presence or absence of gloves (G1, G2)), on the perceptual effort evaluation (RPE), muscle loading level (%MVC), and the risk factor evaluation (%MVC). (%MVC) [biceps brachii and the left and right lateral erector spinae muscles of the back] and the stress on the fifth lumbar vertebra and the first sacral vertebra (L5/S1), to investigate the subjective perception and physiological changes of different hand-held positions on the subject's work. The results showed that the hand-held position and material weight had significant effects on perceptual effort rating (RPE) and muscle load level (%MVC), while the presence or absence of gloves had no significant effect on either of them. P3 without hand hole was the highest, and P1 and P2 with hand hole had lower load; the weight factor had the most significant effect on the margins of the left erector spinae, followed by the right erector spinae, and the biceps was least affected by the weight factor. The analysis of the lumbar spine force assessment showed that the highest pressure stress value of 3443.06 NT was applied to the lumbar spine (L5/S1) when the weight of the material was W1 at the P3 position, and the lowest pressure stress value of 3149.73 NT was applied to the lumbar spine (L5/S1) when the weight of the material was W1 at the P2 position, effectively reducing the risk of lower back pain. Through the analysis of the experimental results, the best psychological and physiological feeling was obtained when the subject lifted both sides of the symmetrical hand hole (P2) position, and the risk score was reduced from 32 to 16 by comparing the difference before and after the improvement through the KIM checklist.