Relationship between casting and machining

Commonly speaking, the raw castings, no matter sand casting parts or gravity sand casting part, have inferior surface quality and rough dimensional precision. Thus sand casting and gravity casting parts always need lots of succeeding machining. Even for some simple casting parts, trimming (polishing), drilling or tapping are usually involved. So a professional aluminum and brass sand casting and gravity casting manufacturer, we set up our efficient and complete machining workshop in the beginning. Besides,Zenith casting gradually introduced various kinds of machining facilities, in order to offer one stop services to save production case and out sourcing cost.

Typical machined castings show

Product catalog: aluminum cast wheel-01(greed sand casting)
Appliance:aluminum machinery part
Marching process: drilling, boring
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Product catalog: aluminum sand casting pulley-02(greed sand casting)
Appliance:aluminum machinery part
Marching process: turning, tapping
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Precision machining equipment list

  • CNC turning Lathe--6sets
  • Versatile turning lathe--3sets
  • Vertical Milling machine--4sets
  • Bench drilling and tapping machine---15sets
  • Grinding machine--1set
  • Polishing machine--4sets

Machining technical database links

link to required machining allowance for raw casting parts of different linear dimension

link to tolerance level of raw casting parts of different linear dimension

Machining glossary

Drilling: Some large holes can be cast out directly, however drilling is necessary when small holes or much high accuracy are required. In addition, holes on different features need to be coaxial, the accuracy obtained by machining may be required.

Tapping: tapping is use to cut out thread in casting.

Counter boring: Counter boring is often done to provide clearance and a bearing surface for the fastener's head.

Countersinking: Countersinking allows for flush mounting of flat head fasteners. Countersinking cannot always be done for very thin stock or for very large fasteners.

Turning: Turning produces solids of revolution which can be tightly toleranced because of the specialized nature of the operation. Turning is performed on a machine called a lathe in which the tool is stationary and the part is rotated.

Facing: Facing is used to describe removal of material from the flat end of a cylindrical part, as shown below. Facing is often used to improve the finish of surfaces that have been parted.

Knurling: knurling is an operation used to produce a texture on a turned machine part. Handles are often knurled in order to provide a gripping surface. The two wheel inserts shown on the tool below contact the work piece, and with pressure, cold-form a pattern into the surface of the part.

Milling: Milling is as fundamental as drilling among powered metal cutting processes. Milling is versatile for a basic machining process, but because the milling set up has so many degrees of freedom, milling is usually less accurate than turning or grinding unless especially rigid fixturing is implemented.

Grinding: Grinding is a finishing process used to improve surface finish, abrade hard materials, and tighten the tolerance on flat and cylindrical surfaces by removing a small amount of material. Information in this section is organized according to the subcategory links in the menu bar to the left. In grinding, an abrasive material rubs against the metal part and removes tiny pieces of material. The abrasive material is typically on the surface of a wheel or belt and abrades material in a way similar to sanding. On a microscopic scale, the chip formation in grinding is the same as that found in other machining processes. The abrasive action of grinding generates excessive heat so that flooding of the cutting area with fluid is necessary.

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