Class parts bush and disk (sleeve and disk) are characterized by the fact that the most common are external and internal cylindrical surfaces. Quotient value (hole length to its diameter):
means that the part is a sleeve (bush). If:
means that the part is a disk type.
In the case of the disk type, the most important type of disks concerns the shape of the disk hub:
- one-sided disk,
- disk with a double-sided hub,
- disk without a hole,
- disk with blind hole.
The technological requirements for the bush and disk are the same. The most serious technological challenges:
- coaxiality of the hole and the external surface – position error (0.02-0.05);
- parallelism of the surface of the faces – position error (0.03-0.05).
The connection and interdependence of the surface: the internal hole and the external cylindrical ones with a specific misalignment error causes that the development of the technological process is difficult. Technological possibilities for accurate hole machining are simpler to implement than existing cylindrical external surfaces as part of existing manufacturing techniques. This is particularly noticeable in the disk type part, where in addition a short hole is an obstacle in fixing the workpiece.
In the machining of holes, including very accurate ones, also use multi-pointed tools (including drills, reamers). Precision machining of external cylindrical surfaces requires many tool passes.
Technological construction of the bush and disk
- The hole should be able to be machined from one fixture, also a stepped bore.
- In series production, for small dimensions, bushings and disks should be machined from commercially available rods. The external surfaces should be designed so that machining is possible from the spindle side after the rod has been extended. With the proper stiffness M-TWTS (Machine Tool Workpiece and Tool System), such a technological solution ensures the best geometrical accuracy of machining, ie meeting the requirements within defined position errors.
- For the disks and bushings of large dimensional dimensions, machining of end faces (base for fixing the object) should be provided.
The general technological processes of bushes and disks
Using the technological capabilities of accurate hole machining, the technological process of the bush and disk should in the first operations ensure the machining of the hole ready. In subsequent operations, the workpiece is fixed on the hole for further shaping and finishing of external surfaces.
The presented below the general technological processes of the parts of the bush and disk class are based on the assumptions of:
- dominant small-lot;
- serial production, hole-technological based.
The basic frame technological process of the bush and disk parts. The workpiece fix on the hole (fig.1):
Technological process of the sleeve and disc parts including heat treatment (fig.2):
Technological process of the bush and disk parts of large dimensions for piece and small lot production (fig.3):
The technological process of the bush and the disk parts of large dimensions for serial production (fig.4):
- Feld M., Podstawy projektowania procesów technologicznych typowych części maszyn, WNT 2000
- Kapiński S., Skawiński P., Sobieszczański, Sobolewski J.Z., Projektowanie technologii maszyn, OWPW2002
- Puff T., Technologia budowy maszyn, PWN 1985