Superoll finishing is a method that smoothes out rough metal surfaces.
The achieved surface finish after burnishing is dependent on the preparation and degree of surface roughness before burnishing.
If the pre-hole operation leaves erratic roughness (high peaks and deep grooves) subsequent flattening of the peaks cannot fill in the deep grooves completely and as a result the finishing quality may be low.
The finishing quality also depends on the shape of the peaks.
Consistency of shapes made by controlled cutting tools with lathes and boring machines create peaks with common heights that are easily flattened, obtaining the highest quality finishes achievable.
In general maintaining closer pre-hole quality directly provides for the best Superoll finishing achievable results, as well the life of the Superoll tool is extended.
Attention to detail to work preparation through the roller burnishing process needs to be considered with a strong relationship between results to each step affecting the final outcome of finish quality.
Superoll is a method to flatten out the rough metal surface, therefore the diameter changes as a result. (The inner diameter expands and the outer diameter compresses).
In order to finish within the dimensional tolerance, it is necessary to calculate the pre-finishing dimension considering this diameter change.
Since the variation of the diameter depends on the material, the hardness, and the burnishing value, conducting tests with several samples and determining the best beginning dimension is recommended.
A Morse taper shank or a straight shank is standard for the Sugino SUPEROLL.
No special driving apparatus is required if the tool can be centered to the workpiece.
Low working torque enables the use of a driving medium with low power, processing can be achieved with general drilling machines, lathes, turret lathes, boring machines, machining centers, drill units, and so on.
When processing with the Sugino SUPEROLL, a metal working fluid with high viscosity (such as light oil) is used. The fluid acts as a lubricant and also washes off fine particles from the SUPEROLL and the surface being burnished. When the working fluid is re-circulated, it is suggested that a filtering device should be installed to remove such fine particles from the oil.
Sugino has developed a "SUPEROLL Oil" exclusively for use in Superoll processing.
If 5% of this fluid is added to light oil or kerosene, superior lubricating qualities will be obtained to lengthen service life to the SUPEROLL.
The Sugino SUPEROLL applies a rolling pressure to the workpiece to impart a fine-grained finish to the surface. To withstand this pressure the workpiece must have sufficient wall thickness (equal to over 20% of internal diameter).
Insufficient wall thickness, even sectionally, will result in waviness or out-of-roundness after processing.
Generally, this problem can be solved through the following methods:
Minimize the difference between the internal and external diameter values before and after burnishing.
Use a jig to support the periphery.
Perform the SUPEROLL process before reducing the wall thickness.
The maximum hardness of a workpiece that can be processed through the Sugino SUPEROLL HRC40.
Processing workpieces with a higher degree of hardness on the SUPEROLL requires considerable working pressure. Working very hard materials can reduce the service life of the tools.
Consequently, to achieve longevity and the required degree of precision in the finished products, it is important that the operation be carried out at the minimum burnishing value.
After a typical burnishing operation with the SUPEROLL the surface hardness increases by Hv40 on an average, imparting a superior and durable surface finish.
The Sugino SUPEROLL is rotated clockwise.
An alternative method of roller burnish processing would be to secure the SUPEROLL and rotate the workpiece instead of rotating the tool.
The standard speed of rotation and feed for the various tool diameters is listed in the following Table.
When burnishing blind holes or stepped shafts using the Sugino SUPEROLL, there will be sections that cannot be worked. These sections are:
The 'R' (radius) section at the end of the rollers
The distance from the end of the roller to the end of the frame
Clearance between the end of the frame and the end surface of the section to be worked
diameter(mm)
SH series
SB series
4.5 ~ 5.7
2.0
---
6 ~ 7.6
2.1
---
8 ~ 14.5
2.5
1.5
15 ~ 34
2.8
1.8
35 ~ 74
3.8
75 ~ 200
5.8
diameter(mm)
SA series
15 ~ 64
1.8
Note:
To minimize any unprocessed section at the base of interior or blind holes please cut or grind down the extending end of the mandrel to be slightly shorter than the end of the rollers.
