Turning clearance angle is changed machining characteristics. In this study, the experiments start from choosing two workpiece materials that are machine structural carbon steel, chrome-molyb- denum steel. Then, the experiments show specifically how features of selected materials changed when they were processed with machining operation. In order to find the surface roughness of workpiece materials, the workpiece materials which have higher tensile strength showed much better value of surface roughness in a surface roughness tester. Moreover, process feed rate was compared between 0.05 mm/rev and 0.10 mm/rev. When process feed rate was 0.05 mm/rev, surface roughness has superior results without reference to the quality of the materials.
In general, as one of judging standard on accuracy of the product, surface roughness is being utilized. However, a forecast of surface roughness is difficult in approaching actually because there are many cutting factors in reality [
Surface roughness in this study means measured value in irregularities parts having been collected voluntarily from the surface of measuring objects, and has very close relation with accuracy on surfaces of the objects. As measuring methods on surface roughness, there are comparative measuring method by comparing with average deviation, stylus trace method, and light sectioning method.
For the parameter which evaluates surface roughness with values, the author intend to use 3 kinds of measuring methods including (μm) as unit, (Rmax) as maximum height of roughness curve, (Ra) as arithmetic mean roughness, and (Rz) as ten point average roughness.
In the surface roughness curve at
Regarding ten point average roughness (Rz), it is marked with two lineal distances by drawing average line which passes through 5th bottom point together with average roughness value which is calculated to 5th highest positions within sampled standard length from the roughness curve.
Roughness testing machine (Model: Kosaka SE-3500) displayed specifications of measuring equipment and its shape at
After coding CNC data for basic processing on used experimental materials, and doing coding work for finish processing by each material again, I intended to get experimental datum.
Model | Contents | |
---|---|---|
Type | KOSAKA SE 3500 | |
Standards | JIS, DIN, ISO, ASME | |
Measuring | Range | Z: 600 μm X: 100 mm |
Magnification | Z: 50 - 500,000 X: 1 - 5000 | |
Speed | 0.5 - 2 mm/s |
Materials | SM45C | SCM415 |
---|---|---|
Specific gravity | 7.85 | 7.85 |
BHN | 170 | 197 |
RHN | 86 | 92 |
Max. tensile strength (MPa) | 585 | 731 |
Yield Stress (MPa) | 505 | 380 |
Young’s Modulus | 205 | 205 |
Poisson’s ratio | 0.3 | 0.3 |
This experiment compared and analyzed arithmetic mean roughness and ten point average roughness values by exempting roughness value of the highest height. Of course, as a result of having compared the highest height and ten point average roughness values, the value was shown same without any unerring.
As a result of comparing roughness values by materials first,
First, as a result of confirming result values on arithmetic mean roughness (Ra) by materials with sequential summing method as shown in
Second, as a result of comparing surface roughness based on processing speeds only after excluding cutting degree angles, SM45C showed most bad roughness among 2 kind of materials like SM45C →SCM415 in order when the feed rate was 0.05mm/rev, and a fact was confirmed same as SM45C → SCM415 in order when the feed rate was 0.10 mm/rev.
Third, when comparing and observing arithmetic mean roughness by integrating totally by materials like
Workpiece | Ra (Arithmetic mean roughness) | ||||||
---|---|---|---|---|---|---|---|
Material | Depth | Feed = 0.05 | Feed = 0.10 | ||||
SM45C | 0.1 | 0.57 | 0.56 | 0.51 | 0.93 | 1.03 | 0.94 |
0.2 | 0.59 | 0.58 | 0.57 | 0.86 | 1.02 | 0.95 | |
0.3 | 0.62 | 0.57 | 0.57 | 0.93 | 0.94 | 0.96 | |
SCM415 | 0.1 | 0.49 | 0.60 | 0.46 | 0.91 | 1.04 | 0.86 |
0.2 | 0.55 | 0.61 | 0.48 | 0.90 | 1.05 | 0.88 | |
0.3 | 0.56 | 0.61 | 0.53 | 0.91 | 1.07 | 0.90 |
Next,
First, as a result of confirming with same methods as above, results like arithmetic roughness (Ra) such like SCM415 → SM45C were confirmed if reviewing the most good result values in order at
Second, if looking into the processing speed by standards only, same results in order of SCM415 → SM45C were confirmed when feed = 0.05 mm/rev and 0.10 mm/rev, and characteristics by material were confirmed definitely from the result.
If summarizing above two article results, there were a little differences in values as a result of doing a comparative analysis on arithmetic mean roughness and ten point average roughness values, but a fact could be known that it came out in order of SCM415 → SM45C equally.
The author tries to compare and analyze Ra and Rz values by dividing surface roughness by each angle having been measured after processing like
After laying the seat which is the tip support in insert holder, a cutting tool as it is, and if seeing processed state, that is, 0.0˚ negative slope angle, comparison state on material roughness set like −6.3˚ and −6.9˚ was divided to two kinds such as Ra and Rz, and researcher displayed them to Figures 6-9 after arranging the datum by angle standards and angles.
Workpiece | Ra | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Material | Depth | Feed = 0.05 | Feed = 0.10 | ||||||||
SM45C | 0.1 | 3 | 5 | 7 | 15 | 40 | 5 | 2 | 4 | 11 | 37 |
0.2 | 3 | 5 | 6 | 14 | 9 | 2 | 4 | 15 | |||
0.3 | 1 | 5 | 5 | 11 | 5 | 4 | 2 | 11 | |||
SCM415 | 0.1 | 8 | 1 | 9 | 18 | 54 | 6 | 1 | 9 | 16 | 45 |
0.2 | 8 | 1 | 9 | 18 | 5 | 1 | 8 | 14 | |||
0.3 | 7 | 2 | 9 | 18 | 6 | 1 | 8 | 15 |
Workpiece | Rz (Ten point average roughness) | ||||||
---|---|---|---|---|---|---|---|
Material | D | Feed = 0.05 | Feed = 0.10 | ||||
SM45C | 0.1 | 2.50 | 3.26 | 2.74 | 4.05 | 4.31 | 3.84 |
0.2 | 2.97 | 3.21 | 3.54 | 4.68 | 4.35 | 3.90 | |
0.3 | 3.72 | 3.79 | 3.33 | 4.31 | 4.17 | 4.24 | |
SCM415 | 0.1 | 2.89 | 3.47 | 2.40 | 4.01 | 4.32 | 3.29 |
0.2 | 2.68 | 3.23 | 2.46 | 3.78 | 4.29 | 3.49 | |
0.3 | 2.71 | 3.77 | 3.22 | 4.01 | 4.43 | 3.75 |
Workpiece | Rz (Ten point average roughness) | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Material | D | Feed = 0.05 | Feed = 0.10 | ||||||||
SM45C | 0.1 | 8 | 2 | 7 | 17 | 36 | 4 | 2 | 6 | 12 | 32 |
0.2 | 7 | 3 | 1 | 11 | 1 | 2 | 6 | 9 | |||
0.3 | 3 | 1 | 4 | 8 | 3 | 4 | 4 | 11 | |||
SCM415 | 0.1 | 6 | 1 | 9 | 16 | 51 | 5 | 1 | 9 | 16 | 53 |
0.2 | 8 | 2 | 9 | 19 | 8 | 3 | 9 | 20 | |||
0.3 | 9 | 2 | 5 | 16 | 7 | 1 | 9 | 17 |
Workpiece | Ra (Arithmetic mean roughness) | ||||||
---|---|---|---|---|---|---|---|
Material | θ | Feed = 0.05 | Feed = 0.10 | ||||
SM45C | 0.0˚ | 0.57 | 0.59 | 0.62 | 0.93 | 0.86 | 0.93 |
0.3˚ | 0.56 | 0.58 | 0.57 | 1.03 | 1.02 | 0.94 | |
0.9˚ | 0.51 | 0.57 | 0.57 | 0.94 | 0.95 | 0.96 | |
SCM415 | 0.0˚ | 0.49 | 0.55 | 0.56 | 0.91 | 0.90 | 0.91 |
0.3˚ | 0.60 | 0.61 | 0.61 | 1.04 | 1.05 | 1.07 | |
0.9˚ | 0.46 | 0.48 | 0.53 | 0.86 | 0.88 | 0.90 |
Workpiece | Rz (Ten point average roughness) | ||||||
---|---|---|---|---|---|---|---|
Material | θ | Feed = 0.05 | Feed = 0.10 | ||||
SM45C | 0.0˚ | 2.50 | 2.97 | 3.72 | 4.05 | 4.68 | 4.31 |
0.3˚ | 3.26 | 3.21 | 3.79 | 4.31 | 4.35 | 4.17 | |
0.9˚ | 2.74 | 3.54 | 3.33 | 3.84 | 3.90 | 4.24 | |
SCM415 | 0.0˚ | 2.89 | 2.68 | 2.71 | 4.01 | 3.78 | 4.01 |
0.3˚ | 3.47 | 3.23 | 3.77 | 4.32 | 4.29 | 4.43 | |
0.9˚ | 2.40 | 2.46 | 3.22 | 3.29 | 3.49 | 3.75 |
First, when feed = 0.05 in SM45C, Ra was changed well in roughness values in order of 0.0˚ → 0.3˚ → 0.9˚, but Ra was changed to 0.3˚ → 0.9˚ → 0.0˚ when feed = 0.10 after Rz was like 0.3˚ → 0.9˚ → 0.0˚, and then Rz was turned into 0.0˚ → 0.3˚ → 0.9˚.
Second, in case of SCM415, Ra was 0.3˚ → 0.0˚ → 0.9˚ when feed = 0.05, and Rz was changed equally like 0.3˚ → 0.0˚ → 0.9˚, and also Ra was 0.3˚ → 0.0˚ → 0.9˚ and Rz was 0.3˚ → 0.0˚ → 0.9˚ in order when feed = 0.10, and so roughness values were changed equally regardless of two feed rates.
This study did an experiment to look into changes of surface roughness by workpiece material by changing cutting edge angles of insert holder which was a processing tool that is, turning clearance angle. Researcher selected two kinds materials such as SM45C, SCM415, and compared surface roughness of selected materials in case of processing them under designated processing conditions.
As a result of having measured surface roughness by workpiece material so as to investigate it, good results were come out from the workpiece material having high tensile strength.
Surface roughness was turned out to be most badly from SM45C in order of SM45C → SCM415. Also, SM45C and SCM415 showed best roughness values all together in case of 0.9˚, and worst values were displayed when the temperature was 0.3˚. Therefore, it is judged that good process criterion could be come out regardless of material kinds that were experimented above if changing negative angles of insert holder seat having been used now to −6.9˚.
Joon-Seong Lee, (2016) Evaluation of Surface Roughness of Metal and Alloy Material. Journal of Materials Science and Chemical Engineering,04,90-97. doi: 10.4236/msce.2016.41013