In a machine base machining plan, when machining the foot plane, the processed one-end end and end face are positioned, and the seat is pressed on the positioning jig with a screw or U-shaped pressure iron (or pressure plate). Correcting the height position of the positioning axis of the spindle shaft can ensure the distance dimension and parallelism of the plane of the foot after machining on the axis line of the machine base. When machining longer or heavier bases, auxiliary support points must be added to reduce the vibration during processing.
In another stand processing scheme, the first step is to machine the foot plane. Before the plane machining of the foot, the casting planes of the inner circle and the outer hole of the frame are not accurate or rough, and appropriate clamping methods must be adopted to ensure that the inner circle and the end hole to be machined after the bottom surface is machined. Around the wall thickness is generally uniform, the specific method: first use the tapered sleeve to roughly align the axis of the frame, and then use the screw jack to adjust the end face and the lower part, and finally use a large nut, screw and three point pressure plate to the frame Fixed it. When machining the foot plane on a planer or gantry milling machine, in order to increase productivity, it is common to mount a number of stands simultaneously on the table top.
Commonly used foot plane processing method
plane. When the foot plane is machined on a planer, the jigs and tools used are relatively simple. Use the bottom plane of the base that is not machined as the rough reference surface, and use the level meter to correct the position of the base. The base must be clamped to avoid loosening due to machining forces or vibration. In order to ensure the high dimensional accuracy of the center of the machine base, the foot plane is processed in two steps of rough planing and fine planing. This kind of processing method has low productivity and is rarely used in large-scale production. For medium and large seats, it is common to machine the foot plane on a planer.
Milling. Milling machine base foot planes on horizontal milling machines, vertical milling machines, portal milling machines and milling power heads are the most common machining methods. Its processing is shown in the figure. The positioning of the inner circle can be achieved by positioning the mandrel or by means of a stop rib 5. The symmetry of the two legs is determined manually. When milling, a large-diameter insert cutter head is used, and the cutting edge of each cutter is not on the same arc and at the same height. In this way, rough machining and finishing machining are performed at the same time, and near continuous cutting, without large vibration, can increase the cutting amount. The maximum cutting capacity is as follows: Cast iron parts can be up to 5~6mm and steel castings can be up to 3~4mm. Normally, the foot can be machined with a single pass. The production efficiency is several times better than planing, and the processing quality is also better.
When the batch is large, the use of a special milling machine to process the foot plane results in higher productivity. Some factories use four-station special iron bed to mill the foot plane and can process four workpieces at the same time.
Mainframes are also often used to cut the foot plane on a horizontal universal tube bed. There are two knives on the tube head, and the cutting edge of each knives is not on the same arc and at the same height. Processing is still intermittent cutting. Slight vibration when the cutting amount is large. This processing method has higher productivity and better quality. Occasionally, the base plane of the mid-sized base is also broached.
Special machine. The typical common organic milling and milling machine uses the processed machine seat and end face clamps for positioning. The milling foot and the drill foot hole are completed at one time.