1) forging fillet
When the blank of a part is a casting, the corner of the intersection of the casting shall be rounded as a result of the requirement of the forging skills. The forging fillet can prevent the sand falling at the corner of the casting and prevent shrinkage and crack when the metal is cooled. The size of the forged fillet is usually R=3~5mm, and can be clearly indicated in the technical request.
2) the die pitch
Manufacturing blank by forging method, in order to remove the sand in the face, usually along the draw direction for about 1 features: 20 slope, called the draft. It also has the corresponding draft in the casting, the inclination to be marked on the map, not necessarily draw, as shown below; when necessary, can request with text in skill.
3) casting thickness
When the wall thickness of the casting is not uniform, the casting will crack and shrink when the casting speed is different. Therefore, the wall thickness of the casting should be as uniform as possible. See the figure above. When it is necessary to choose different wall thickness connections, the method of gradual transition shall be adopted. The wall thickness of the casting is usually used to directly obtain scale.
Mechanical construction of 2. parts
1) the groove of the cutter and the grinding wheel pass over the groove
In parts cutting, in order to facilitate the withdrawal of tools and ensure that the parts of the contact surface close, at the processing of the surface of the steps should be pre processed groove or grinding wheel groove. The groove of the cutter in turning the outer circle can be marked by "groove width * diameter" or "groove width * groove depth". The grinding wheel grinding circle and the outer circle and the undercut.
2) drilling structure
A blind hole drilled with a drill bit has a cone angle of 120 degrees at the bottom. The drill hole depth refers to the column. Some of the depth does not include the cone hole. At the transition of the stepped hole, there is also a cone angle 120 degree frustum of a cone, and its drawing method and scale injection method.
When drilling with a bit, request the axis of the drill to be perpendicular to the drilled end face to ensure accurate drilling and to prevent the bit from breaking. The accurate construction of three kinds of drilling faces.
3) lug and dent
The contact surfaces of parts with other parts are usually machined. In order to reduce the machining area and ensure good contact between the parts, it is often planned that the lugs and pits are formed on the casting. A method of supporting a face, projection, or support surface; a groove structure in order to reduce machining area.