Category Archives: Manufacture

Components of CNC Machined

CNC machining shows the process failure that preceded it. Expensive in terms of energy and labor, waste of basic resources and requires a lot of expensive capital equipment, he maintains his main position in production engineering simply because of his flexibility and comfort, and because of his ability to make up for the shortcomings of other processes. Quite naturally, the reduction in machining by other means forms a near-shape net, with an enhanced surface finish, constantly needed.

In normal manufacturing, machining has the ability to combine high quality with large throughput. Its technical flexibility is such that almost any shape can be produced from a solid block of material provided the price can be paid (although hollow shapes are limited), and cnc machining is frequently adopted for the manufacture of prototypes and one-off items. Sometimes, machining is used for the bulk manufacture of a part which has a shape inappropriate for any other forming process: in this case redesign should be sought if at all possible.

The costs of machining a bought-in blank or semi-finished product is a choice between, on the one hand, achieving a given shape by machining it from a simple, largely unformed blank and, on the other hand, carrying out a mainly finish-machining operation on a blank which has already received much of its shape from some other process. In the first case the cost of the blank is low but the machining yield is also low. In the second case the reverse applies, with the unit cost of the preformed blank generally being lower, the larger the scale of production. If there is to be a real choice between two such processes then the two curves must intersect. Consider, for example, a steel part which may be produced with equally satisfactory properties by automatic machining from plain bar stock, or finish machining of steel forgings. One factor which greatly influences machining costs is the machinability of the material. This can be influenced by the metallurgist, the purchase of freemachining steel bar stock containing sulphides greatly reduces machining costs (although at the expense of some degradation of mechanical properties as compared with the forgings).

Considering competition between different materials it may be noted that a high scrap value of the swarf reduces net machining costs. Titanium is expensive to buy, but the scrap value of titanium swarf is negligible, and it is therefore not economic to shape titanium extensively by machining methods. This is not true of aluminium alloys, which are often competitive with titanium.

The ease with which a material can be machined to the desired shape is an important consideration in material selection because it influences manufacturing costs. Machinability is not a property of the material, but an attribute that quantifies the machining process. Machinability directly affects surface finish and dimensional accuracy, which are important factors for any cnc machined component and are included on the engineering drawing. Tool life and cutting speeds affect production rates and cost, making them valuable considerations to be included during the design of cnc machined components.

The material is considered good for machining if the tool wear is low, the pressure applied is low, and the chip breaks into small parts. The ability of the engine is influenced by the strength of the material, the presence of lubricants such as lead, sulfur, phosphorus, and graphite. The presence of abrasive constituents such as carbide reduces machinability. Chisel geometry and processing conditions such as cutting speed and lubrication impact machinability. In practice, carbon steel AISI 1112 is rated machinability 100 at cutting speed which provides 60 minutes of tool life. Consider this in terms of the level of production it provides for the life of the tool 60 minutes when done at a cutting speed of 100 feet / minute. Machine rating or comparison with other materials provide a relative measure of their processing procedures.