| 摘要 |
刀具狀態的監控在切削工具機中是很重要的一環，其目的是為了避免造成產品精度下降，良率降低。眾多研究如聲射訊號監測(Acoustic
emission)或是切削力(Cutting forces)與震動(Vibration)的觀察以及切削溫度(Cutting
temperature)的改變等方式常被用來做為在線監控指標。其中，切削溫度監控的方式在業界長久以來卻無法被接受，主要原因是量測溫度的方法大多會增加成本。舉例來說，使用熱電偶量測切削溫度，必須於刀片上鑽孔並深入至刀尖處，而後再將熱電偶埋入。此種做法會使得換刀時間增加且提升加工成本。若使用熱感測儀器，此儀器本身造價昂貴，且在切削環境下易受到切屑干擾測溫，並不適合。然而，切削溫度卻又是很有效監控刀具狀態的物理量，因為一旦刀具發生磨耗或崩損，多餘的磨擦熱會產生，造成溫度上升。有鑑於此，本研究之目的為增加切削溫度在線監控的可行性。
針對此問題本研究利用遠端熱電偶偵測技術(Remote thermocouple sensing
technique)來克服並開發一套適用於在線監控切削溫度之方法。建立間接量測到的切削溫度與實際切削溫度之間的數學模式關係，並且將熱電偶置於刀面下方，量測間接切削溫度，再以此間接切削溫度估算刀尖溫度。此溫度預估方法優點為不受被切材料的材料物理性質所限制，也無需裝設昂貴的動力計來擷取切削力輔助計算。只要知道刀片的材料物理性質、接觸面積大小、間接(遠端)切削溫度，即可對刀尖溫度進行預估。
由實驗結果可知，非切削實驗的溫度預估誤差在5%以內；車削1045中碳鋼的誤差為2%左右。且可於開始加工後五秒預估穩態溫度。最後本研究也進行切削速度改變的實驗，在溫度變化的情況下，其預估結果仍有一定準確性，誤差約在5~8%左右。
關鍵字：切削溫度、在線監控
Monitoring of cutting tool
condition is very important for the efficient operation machine.
The purpose of monitoring is to increase the precision and
quality of the products. A great deal of research revealed that
signal detection of acoustic emissions, cutting forces, cutting
vibrations and cutting temperature, are often used as indicators
in on-line monitoring. Monitoring cutting temperature always
increases the cost of products, which is unacceptable in the
industry. For instance, the most common method is to drill a
hole close to the cutting edge of cutting tool and insert a
thermocouple. However, this would increase the cost of machining
operations. Another way is to use an infrared thermometer, but
chips often obstruct the view of cutting edge and the equipment
is very expensive. However, measuring the cutting temperature is
a very effective for monitoring the status of inserts. Once the
tool is worn, its temperature rises. The purpose of this study
is to increase the feasibility of cutting temperature
monitoring.
In this study, the objective of this research is to use remote
thermocouple sensing technology to overcome this issue and
develop a system of on-line monitoring of cutting temperature.
By measuring the temperature with a thermocouple placed under
the inserts, we can estimate the temperature of the edge of the
cutting tool with a proper mathematic model. Therefore, we will
be able to monitor the temperature of the cutting tools. The
advantage of this method is that temperature measurements are
not affected by the material properties of the workpiece. And
the need for expensive equipment like dynamometer is eliminated.
To estimate cutting edge temperature, the only information
required is the material properties of the cutting tool, the
contact length and the remote temperature.
The experimental results show that the non-cutting tests are
within 5% error and cutting experiments within 2% error.
Steady-state temperature can be estimated in 5 seconds. Finally,
errors in the cutting test when the cutting speed changes from
140 m/min to 320 m/min are 8%.
Keywords: Cutting temperature, On-line monitoring
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