Star Micronics to Launch the SD-26, a CNC Swiss-Type Automatic Lathe
– Expanded area for gate-shaped gang tool model, and a lineup of 4 types to suit your complex machining needs –
Star Micronics has developed the SD-26, a new model Swiss type automatic lathe(*1) capable of up to 26-dia. machining. It is mainly targeted at complex-shaped parts for automotive, hydraulic/pneumatic equipment and medical-related uses, and will be available for sale worldwide from April 2023.
The SD-26 employs a gate-shaped tool post with a cross-guide structure(*2) that distributes the load evenly, arranged on the gang-type tool post for front-end machining so as to surround the guide bush that is the machining point for various tools such as turning tools and drills. The following 4 types are available, allowing you to select the most suitable tool post specification according to the application of the workpieces.
| ① “Type S”: |
Equipped with a 4-spindle facing-type milling unit with a tool swivel control axis (B-axis) capable of programmable simultaneous 5-axes control The upper section has one cartridge-type position with a 2nd B-axis mechanism that can provide swivel control for the dedicated tool unit. Various types of tool units can be mounted, including the world-first twin-thread whirling unit. |
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| ② “Type G”: |
Equipped with a 4-spindle facing-type milling unit with a tool swivel control axis (B-axis) capable of programmable simultaneous 5-axes control The upper section has two cartridge-type positions capable of mounting various tool units of existing models. *The two cartridge-type positions are common to types G/E/C. |
| ③ “Type E”: | Equipped with a 4-spindle facing-type milling unit with a tool swivel control axis (B-axis) capable of programmable simultaneous 4-axes control |
| ④ “Type C”: | Equipped with 4-spindle facing-type milling unit for which the angle is manually adjustable. |
In addition, this type employs a guide bush/non-guide bush switching mechanism to flexibly support the increasingly diverse parts machining needs. This allows you to freely switch between the guide bush specification, which acts to prevent deflection of materials, enabling high accuracy machining of long and narrow parts such as motor shafts, and the non-guide bush specification(*3), which enables machining of short parts such as nuts without wastage, reducing the amount of waste material to be disposed of, on a single machine.
Furthermore, the machine has various features designed to offer enhanced workability and operability for the operator from both a hardware and software perspective, such as a reconfigured machine structure for improved access to the guide bush and tool post, a function for batch input/output of NC programs together with related information such as offset data, and various help functions including a command help function that allows you to check the various commands on the NC screen.
Main features
High functionality
- You can select from 4 types for the optimum specification according to the shape of workpiece, from the “Type S”, which is equipped with 4-spindle facing-type milling unit with B-axis control capable of simultaneous 5-axes control and cartridge-type tool unit with B-axis control mechanism, through to “Type C”, equipped with a 4-spindle milling unit for which the angle is manually adjustable.
- For the cross drilling unit on the front side, you can select from two types: the 4-spindle type dedicated for cross drilling, and the cartridge-type 4-spindle type on which tool units from existing models can be mounted. (Type S has the cartridge-type 4-spindle type only)
- A 8-spindle unit with Y-axis control is mounted for machining on the back side. The rotating tool unit can be mounted on all 8 positions, for expanded complex machining capability on the back side.
- An optional two turning tool holder can be mounted on the 8-spindle unit with Y-axis control. Enhanced turning capability on the back side realizes efficient division of machining on the front and back sides.
- The machine is equipped with our proprietary control method, the Star Motion Control system. (Types S and G) NC control is used to drastically reduce the required calculation time during operation and non-cutting time such as tool selection time, shortening the cycle time per part and achieving reduced energy consumption.
High rigidity and accuracy
- The 4-spindle facing-type milling unit with B-axis control employs a structure for holding the upper and lower ends, and maintains unit hold rigidity during swivel machining.
- The main and sub spindle employ a built-in spindle structure, realizing improved indexing accuracy.
- The machine employs various functions to maintain machining accuracy, such as flexible thermal displacement correction using temperature sensors arranged on each section of the machine body, and a dimension assist function that automatically corrects dimensional changes during temporary machine stoppages.
- The gate-shaped tool post for front side machining employs a cross-guide structure with an evenly distributed load. This reduces the moment load on the tool post guide rail during cutting, maintaining tool post rigidity.
- The Star Motion Control System’s spindle control utilizes the machining time of the previous stage to select the tool for the next stage and complete the approach, which suppresses vibration from excessive deceleration during spindle movement. (Types S and G)
NOTE 1: Swiss-type automatic lathe
The Swiss-type automatic lathe was devised as watch component processing machinery in Switzerland in 1870s. Known as a “sliding head-type automatic lathe” as well, it has remarkable characteristics of high-precision cutting of components with longer length compared with the diameter.
In general, if long and narrow parts are processed with a general-purpose lathe, flexure will occur on the workpiece, making finishing with the correct dimensions impossible. The Swiss-type automatic lathe utilizes a guide bush to function as a material steady rest. The tool, positioned at a certain distance from the guide bush, gives a cutting motion only the direction of outside diameter. This allows the workpiece to be cut accurately with no flexure. As for axial motion, the headstock, rather than the tailstock, moves while clamping a workpiece.
NOTE 2: Uniform load cross guide structure
The gang-type tool post of the CNC automatic lathe is composed of X-axis and Y-axis slide tables. Each axis is usually supported by four linear guide bearings (eight linear guide bearings in total).
The uniform load cross guide structure indicates a structure of the tool post equipped with 8 linear guide bearings evenly arranged around the guide bush as a cutting point to generate a load. By distributing the cutting load to eight linear guide bearings, the load applied to each linear guide bearing is minimized and the tool post rigidity is improved.
The employment of this tool post structure enables extended continuous operation with stable accuracy and prolongs the service life of the linear guide bearings.
NOTE 3: Non-guide bush type
This is a sliding head-type automatic lathe which is designed based on the Swiss-type automatic lathe with a guide bush dismounted. Without a guide bush, it is not well suited for machining narrow and long parts. If the workpiece is short and does not deflect, however, such material can be handled effectively.
With the Swiss-type automatic lathe, the rear side of a bar material needs to be handled as waste as a portion equivalent to the size of the guide bush structure which functions as a steady rest for the material cannot be machined.
The non-guide bush type reduces the waste to about 1/3 in length compared to the waste made by the guide bush type.