Mingte Machinery Processing Factory is a physical processing factory with nearly 20 years of industry experience. In daily production, it will also encounter many professional problems or difficulties. Under the operation of professional technicians in the factory, they have been well solved one by one. In order to make more colleagues smoother in processing, we have also specially summarized some processing experience for your reference. Today, I will share with you the common sense of workpiece installation.

In order to process a surface that meets the specified technical requirements on a certain part of the workpiece, before machining, the workpiece must occupy a correct position on the machine tool relative to the tool. This process is usually called the "positioning" of the workpiece. After the workpiece is positioned, due to the effects of cutting force, gravity, etc. during processing, a certain mechanism should be used to "clamp" the workpiece so that its determined position remains unchanged. The process of making the workpiece occupy the correct position on the machine tool and clamping the workpiece is called "installation".

The quality of workpiece installation is an important issue in mechanical processing. It not only directly affects the processing accuracy, the speed and stability of workpiece installation, but also affects the productivity. In order to ensure the relative position accuracy between the machining surface and its design datum, the design datum of the machining surface should occupy a correct position relative to the machine tool when the workpiece is installed. For example, in the process of fine turning the ring groove, in order to ensure the circular runout requirements of the bottom diameter of the ring groove and the axis of the skirt, the workpiece must be installed so that its design datum coincides with the axis centerline of the machine tool spindle.

There are various installation methods when machining parts on various machine tools. The installation methods can be summarized into three types: direct alignment method, line alignment method and fixture installation method.

(1) Direct alignment method When this method is used, the correct position of the workpiece on the machine tool is obtained through a series of attempts. The specific method is to install the workpiece directly on the machine tool, use a dial indicator or a needle on the needle plate to visually correct the correct position of the workpiece, and align while checking until it meets the requirements.

The positioning accuracy and alignment speed of the direct alignment method depend on the alignment accuracy, alignment method, alignment tool and the technical level of the workers. Its disadvantages are that it takes a lot of time, has low productivity, and requires experience to operate, and has high requirements on the workers' skills. Therefore, it is only used in single-piece and small-batch production. For example, alignment by imitating the shape belongs to the direct alignment method.

(2) Scribing alignment method: This method uses a marking needle on the machine tool to align the workpiece according to the line drawn on the blank or semi-finished product to make it obtain the correct position. Obviously, this method requires an additional scribing process. The drawn line itself has a certain width, and there is a scribing error when marking. There is also an observation error when correcting the workpiece position. Therefore, this method is mostly used in rough processing where the production batch is small, the blank precision is low, and large workpieces are not suitable for the use of fixtures.

(3) Fixture installation method: The process equipment used to clamp the workpiece so that it occupies the correct position is called a machine tool fixture. The fixture is an additional device of the machine tool. Its position relative to the tool on the machine tool has been pre-adjusted before the workpiece is installed. Therefore, when processing a batch of workpieces, it is not necessary to align and position them one by one, and the technical requirements of the processing can be guaranteed. It is both labor-saving and trouble-free. It is an efficient positioning method and is widely used in batch and mass production. Our current piston processing uses the fixture installation method.