What is Modular Machine Tool?

Since the common components have been standardized and serialized, they can be flexibly configured according to needs, which can shorten the design and manufacturing cycle. Therefore, modular machine tools have the advantages of low cost and high efficiency, are widely used in mass and mass production, and can be used to form automatic production lines. Figure 1 shows the composition of a curved modular machine tool. Modular machine tools are generally used to process special or box-shaped parts.

During processing, the workpiece generally does not rotate. Drilling, reaming, countersinking (see drilling), reaming (see reaming), and boring are performed by the rotary motion of the tool and the relative feed motion of the tool and the workpiece. See boring), plane milling, internal and external thread cutting, and external circle and end face machining. Some modular machine tools use a rotary head to hold the workpiece for turning, and the tool performs the feed motion.

It can also do the outer circle and end surface processing of some rotating parts (such as steering wheel, car rear axle half shaft, etc.).
Since the 1970s, with the development of indexable tools, closed-tooth milling cutters, automatic bore size detection, and automatic tool compensation technology, the machining accuracy of modular machine tools has also improved.

Milling plane flatness up to 0.05mm/1000mm, surface roughness can be as low as R< A 2.5 – 0.63 microns; boring accuracy up to IT7 ~ 6 degree pitch accuracy up to 0.03 to 0.02 microns.
Brief historySpecial machine tools developed with the rise of the automobile industry. In the special machine tool, some parts gradually develop into general-purpose parts due to repeated use, resulting in the combined machine tool. The first modular machine tool was made in the United States in 1911 to process automobile parts.

In the early days, each machine tool manufacturer had its own common component standards. In order to improve the interchangeability of common parts from different manufacturers and to facilitate user use and maintenance, Ford Motor Company and General Motors of the United States negotiated with American machine tool manufacturers in 1953 to determine the principle of standardization of common modular machine tool parts, that is, they strictly stipulate each The size of the connection between the components, but the structure of the components is not specified. In 1973, the International Organization for Standardization (ISO) published the first batch of common component standards for modular machine tools.

In 1975, China’s First Ministry of Machinery Industry promulgated China’s first batch of common component standards for modular machine tools. This standard comprehensively considers the needs of various industries such as automotive, agricultural machinery, textiles, and instrumentation, and has a wide range of applications.
General Parts “General parts are divided into 5 categories according to their functions: power parts, support parts, transport parts, control parts and auxiliary parts.
Power components provide the main motion and feed motion components for the modular machine tool. It mainly includes power box, cutter head and electric sliding table. Power box: Its function is to transmit the rotational movement of the motor to the spindle box.

The spindle box is a special component designed according to the process requirements, and usually has a few to tens of spindles to install tools. Cutter head: Its function is to transmit the rotational motion of the motor to the spindle after deceleration, which is used for single-process processing, including drilling heads, milling heads, tapping heads, boring and rotary heads.

Power Slide Table: It is used to install the power box or cutter head to realize the feed motion of the tool. The electric sliding table has an ordinary sliding table with the table moving along a single axis and a transverse sliding table with the table moving along two mutually perpendicular axes, which are driven by lead screws, cams, hydraulics, pneumatic and pneumatic.
Support parts used for the installation of electric guides, feed mechanism cutting heads or fixtures, etc., including side bases, intermediate bases, brackets, adjustable brackets, columns and column bases, etc.
To transport the components used to transport the workpiece or headstock to the processing station, there are indexing rotary table, ring indexing rotary table, indexing drum and reciprocating table, etc.
The control component is used to control the automatic work cycle of the machine tool, including the hydraulic station, electrical cabinet, and console, etc.
Auxiliary components include lubrication device, cooling device and chip removal device, etc.
Configuration type The basic configuration type of modular machine tools has two types, single station and multi-station, and there are multiple configuration methods in each type.
Single-Station Modular Machine Tool The workpiece is clamped on the fixture of the machine tool, and the power components are arranged according to the number of surfaces (single-sided and multi-sided) and positions (horizontal, vertical and inclined) to process (Figure 1).

This kind of single station modular machine tool can generally only process each processing part at the same time, which can ensure the high mutual position accuracy of each processing surface, and is suitable for processing large and medium-sized box parts. .

Multi-station modular machine tool, the workpiece and its accessories are sequentially sent to each processing station by the workpiece conveyor, which can process the processing workpiece multiple times. This kind of machine tool is generally equipped with a separate loading and unloading station, so that the auxiliary time and the maneuvering time overlap, the productivity is high, and it is suitable for the mass production of various medium and large workpieces. small with complex shapes.

Multi-station modular machine tools are divided into 4 types according to the conveying parts (Figure 2). Rotary Workbench Combination Machine Tool: Work is transported from the indexing rotary table to each station for sequential processing.

Power components are distributed across the workbench according to the process and can be installed horizontally or vertically. This machine tool is suitable for multi-process processing of the top and side surfaces of the workpiece. Drum wheel modular machine tool: The workpiece is clamped to the edge or end surface of the drum, and the rotation axis of the drum is often installed horizontally. Power components are arranged on both sides of the drum. Through the rotary indexing of the drum, the work piece is sent to each station for processing in sequence.

This type of machine tool can process from two opposite directions at the same time, such as placing power components in the radial direction of the drum, and also process from the third direction. Center column type modular machine tool: the workpiece is transported by the circular indexing rotary table. Power components are installed on the polyhedral column in the center of the workbench, and horizontal or tilted power components can also be placed around the workbench. This machine tool is suitable for processing complex workpieces with mutually perpendicular holes and faces, and horizontal power components can be placed in the center of the worktable when the center column is not used.

Reciprocating workbench combination machine tool: the workpiece is carried by the reciprocating workbench, and the power components are arranged on both sides of the workbench, generally two stations; If the mobile workbench adopts proper positioning mechanism, it can also become a three-station bench. This type of machine tool can only have one station for processing at a time, and the loading and unloading time cannot overlap with the processing time. It is suitable for medium batch production of medium and large workpieces.

Combined Machine Tools for Small and Medium Batch Production For the combined machine tool to be used in small and medium batch production, it is often necessary to apply group technology to concentrate workpieces with similar structures and processes into one combined machine tool to improve the utilization rate of the machine tool. There are two common types of machine tools.

Replaceable head type modular machine tool: the machine tool is equipped with various types of head storage libraries (rotary, stepper, multi-segment store), and the head in the power box is replaced by the transport device and device replacement (Figure 3).

Turret-type modular machine tool: Install multiple heads on the turret edge surface, automatically index according to the process, and perform multi-process fine and rough processing on one side of the workpiece (Figure 4). After one surface is finished processing, the workpiece is indexed and the other surfaces are processed in sequence. (see color image)

Modular Machine Tool Automatic Line for Processing Upper Body of Fuel Injection Pump
Development Trends The main development trends of modular machine tools are: Adopting adjustable-speed motors and pairs of ball screws to simplify the structure and shorten the production cycle; Use a digital control system and an automatic head and accessories replacement system to improve the adjustment of the Sex process; Incorporate into flexible manufacturing system