Used Jig Boring Machine for Sale — 63

Jig Boring Machine - Metalworking

In appearance and construction, the boring jig machine looks similar to a vertical milling machine but is far more accurate and rigid, especially the spindle of a boring jig is very rigid to resist deflection. A typical jig boring machine consists of a heavy base and a column. At the top, the column carries the spindle which exhibits up & down movement along the vertical guideways. Anti-friction bearings are installed to take care of the radial and axial loads to which the spindle is subjected to. The table mounted over the addle moves in various directions along the guideways present on the saddle. Longitudinal motion to the work is given by moving the table while cross movement is provided by moving the saddle. The vertical movement is by the upward and downward motion of the spindle.

Jig Boaring Measurement Systems & Machines

Devices with stable and adjustable end gauges and indicator sensing units are used on jig-boring machines for precise and accurate measurements. The commonly used measurement systems in a jig boring machine are discussed below:

• Precision Lead Screw system: This kind of measuring system which is provided underneath the table consists of a lead screw, a graduated micrometer dial, and a vernier at its end. The advantage of this system is the usage of compensators whose primary function is to correct and sometimes eliminate the errors in table movements. But the major limitation of this measurement device is that it is limited to only small tables.
• End Measurement system: End measurements are carried out by accurately finished rods and end adjustments are performed with the help of micrometers. For correction, the end measures and the micrometer are placed between the dial indicator on one side and an adjustable stop on the other side of the table. The table is then moved until the dial indicator reads zero. As it is versatile and can be used on all sizes and lengths of tables, it more preferred over the precision lead screw system.
• Scale and Microscope system: In this system, accurate graduated scales and a microscope are incorporated in the machine for accurate movement of the table. Measurements are performed accurately by the microscope. As there is no usage of wearing parts, the system is highly accurate.
• Electromagnetic system: The system consists of two equispaced bars carrying electromagnetic projections. A precision micrometer fitted just below the table is fastened to a magnetic head for zero reading. When the magnetic centre of a projection is just in front of the head, the meter reads zero. It can be termed as a quick adjusting system as it ensures rapid traverse of the table and the saddle.

Types of Jig Boring Machines

Vertical jig boring machines are the extensively used machines for boring, reaming, counter sinking of holes in jigs, dies, fixtures and other similar tools. It can also be used for carrying out light milling operations as well. A precision jig boring machine consists of an inclined rotary table in addition to a plain rotary table. The size of the boring machine is generally specified by the diameter of the spindle but in the case of vertical boring machines, the dimensions of the column height and table size should also be mentioned. Similarly, Horizontal boring jig comes into play in horizontal boring and milling processes.

Jig Machine is Useful

One of the prominent advantages of jig boring machines is that it can maintain accuracy between multiple holes and surfaces. With the help of the aforementioned measurement systems, positioning of upto 0.003 mm can be achieved directly from the drawing in a typical jig machine. Tolerances can also be held tightly within 0.005 mm. When designing a part with holes, it is important to determine what holes must be jig bored. The reason behind this is that jig boring operation requires extra time and attention, and the jig boring machine at the machine shop may have a back log of jobs. Jig boring thus has a big impact on the lead time of a part. Ultimately, jig boring machines are characterized by less productivity because of high cycle time but it is greatly compensated by the accuracy provided by the machine. Also to prevent the influence of ambient temperature changes on accurate machining, the temperature is constantly maintained at 20◦ C by installing the jig machines in insulated areas with special environmental enclosures.

Few jig boring machine manufacturers in the world are: MAG, YASDA, Kitamura Machinery, SIP, MITSUI SEIKI, Willemin-Macodel and SHE HONG.