One, the function of numerical control equipment that principle of adaptability of craft of craft adaptability principle basically points to to place is chosen must suit to be mixed to produce the demand such as metre by precision of the shape size of treatment spare parts, dimension. Shape size adaptability. Chooses numerical control equipment must can suit to be machined the spare parts is logical the shape size requirement of group of groups. Undertake on the foundation that this should be being analysed by craft of treatment spare parts, what the attention wants here is to prevent to pay high price as a result of redundant function. Machine precision adaptability. Chooses numerical control equipment must be satisfied by treatment spare parts group the precision requirement of the group. Machine precision to assure not out of tolerance, the index of precision of numerical control equipment that must inspect manufacturer home to give out makes sure the reserve that has 1/3 is measured. But should notice not to seek needless high accuracy blindly, want to be able to ensure only spare parts group the treatment precision of the group is OK. When inspecting the precision index that numerical control equipment gives out, wanting those who use to notice is what standard. The commonly used precision standard on international has ISO, JIS, ASME and VDI(cent to belong to international, Japan, United States and Germany) , still have the BS of Chinese GB and England in addition. Produce metre adaptability. Will decide according to machining the batch of the object and metre requirement is will complete treatment with equipment of a numerical control, still choose equipment of a few numerical control to complete treatment, perhaps choose flexible and unit, flexible production system will complete treatment, perhaps choose flexible special machine tool and product line, special product line will complete treatment. The biggest characteristic of numerical control equipment is to have flexible change and flexibility, suit take turns production and product to change most fast requirement. If product lifecycle is longer and batch is big, choose private plane, special railway line to make sure productivity and manufacturing metre requirement are more reasonable perhaps. Choose numerical control equipment to notice the metre between fluctuation working procedure is harmonious and consistent even, the environment propping up such as the configuration that should notice peripheral equipment, process designing, operation, maintenance. If they are irreconcilable,move, again fine numerical control installation also cannot produce effect well. 2, the market has rate principle market to have the numerical control equipment with high rate to explain is flourishing sells a product, already got the favour of most user and affirmation, won't have the case with too much inferior quality commonly. The market has the flourishing with high rate to sell numerical control equipment must be batch product, its design structure and technology basically is the course is revised for many times with test, should be more mature product, product quality should can get assuring. 3, the dependability of equipment of dependability principle numerical control is the focal problem that user of equipment of broad numerical control cares particularly, because this must be treated seriously when choosing numerical control equipment. Whether does numerical control equipment pass dependability assessment, the level of average time to failure that whether reachs national regulation (the regulation is 500 hours of) . Is most user evaluated to dependability of equipment of some kind of numerical control how? Decorate in what Chinese quality runs committee of user of association whole nation below, committee of user of machine tool of countrywide numerical control has organized satisfaction of user of numerical control equipment to spend an evaluation to equipment of a few numerical control, the person that the average score that the user evaluates achieves 80 minutes of above just thinks to be approbated by user place, do not prevent when equipment of choose and buy seek advice to committee of user of machine tool of countrywide numerical control. 4, the configuration that optimizes equipment of configuration principle numerical control should be satisfied already be asked by the function of treatment spare parts, want to make sure quality is stable and reliable again, achieve economy even reasonable. Whether is rigid structure designed through optimizing, the construction is reasonable, whether to have enough tigidity and stability, whether to choose high grade material and effective craft processing, in order to assure its stability, undertake making an on-the-spot investigation to these answering. The configuration detailed list that should ask numerical control equipment produces manufacturer to offer products of all sorts of crucial form a complete set and manufacturer home (the) after be being added in the contract, prevent manufacturer of numerical control equipment the home is shoddy, the effect is overall quality. Product of form a complete set is chosen in the superior goods that answers to be produced from batch of domestic and international famous manufacturer, especially system of numerical control system, drive of feed servo, main shaft, main shaft and ball guide screw use system of guide screw of bearing, ball, PC to reach electric, fluid casting die, must select the product of form a complete set that good batch produces. 5, maintenance spare parts supplies a principle to be told to importing numerical control equipment, the user often encounters maintenance spare parts to supply difficult question. Or is to supply channel not free, supply time cycle to grow, the spare parts that or was before already fell into disuse, manufacturer makes price of this kind of spare parts technically very costly, or cannot be done namely. Settlement way should consider the following case: The first, fragile to the key when order goods should order maintenance spare parts at the same time; The 2nd, the supplier can protect duty library to supply spare parts through Chinese spare parts, but at any time choose and buy; The 3rd, the function can be offerred to replace spare parts with reasonable price after the supplier should make sure spare parts falls into disuse or design adoption spare parts formerly, the loss that causes otherwise also is considerable. 6, when quality makes sure the principle chooses numerical control equipment, not only the quality that should assess itself of numerical control equipment, assess numerical control equipment to produce the perfect sex of company quality guarantee system and authentic sex even. Equipment of assessment numerical control is overall the attestation that produces an enterprise to whether adopt ISO9000 relevant specification. Because, whether to pass the attestation of ISO9000 relevant specification, the difference that assures to the quality of company product is very big. Pass attestation, make sure in quality management and quality the metropolis on corporeal condition gets assuring in the round. Equipment of assessment numerical control is overall the moving situation that produces company quality system. The quality administrator of the technologist that equipment user should set by numerical control when choosing equipment of great and costly numerical control and own enterprise arrives jointly manufacturer of numerical control equipment undertakes making an on-the-spot investigation on the spot. Equipment of assessment numerical control is overall the component that produces a business contracts square. Namely the attestation that product of numerical control equipment complement produces an enterprise to whether adopt ISO9000 relevant specification, what need product of form a complete set to should be chosen from the business that carries ISO9000 standard attestation match. Equipment of assessment numerical control produces enterprise tooling standard. Tooling is the method of important goods and materials that assures product quality. Accredit quality supervisor. To equipment of great and costly whole set numerical control, after make choice of produces a business, can send the quality administration expert that has experience to garrison this enterprise with the identity of quality supervisor when necessary, link of crucial to the key quality undertakes censorial, produce quality in order to assure, avoid to cause a loss. 7, when principle of maintenance service network is choosing numerical control equipment, mix before the carry out that must assess numerical control equipment to produce enterprise and product of its form a complete set to produce a business after service network is perfect, whether can the quality that serves a team be competent the job, service whether seasonable, whether can fulfil commitment. This are very important, not allow to ignore, should try to make clear in contract provision, regulate matter of claim for compensation. Serve a site to maintenance is being done not have in China, although have,perhaps maintain a site, but the business that drives not to act well with nominal, in principle cannot order goods. 8, avoid risk principle technical risk. To one technology is sophisticated and costly numerical control equipment, the method that joins key project should be adopted to sign technical contract and business affairs contract when choosing. Technology is made before the requirement orders goods design, dynamic imitate is emulated or real cogent test, supplier of the requirement when ordering goods provides complete set craft and cutting tool, after arriving, ask responsible installation is debugged, the process designing that the requirement is in charge of operating personnel, operation grooms with what safeguard, the requirement is in charge of what the model machines a spare parts trying cut, ask with satisfying user spare parts to machine entirely continuously and till manufacturing metre requirement and stability are used at production. The supplier dare assume such handing in key contract, also be the stern test of pair of their actual strength. Avoid financial condition risk. In the spring tide of goods economy, of fraud and trap or existence, go in not carefully with respect to meeting defect, the result cannot be explained to leader and worker. To avoid this kind of risk, want to undertake making an on-the-spot investigation on the spot to the supplier. Besides making an on-the-spot investigation to product technology quality and service quality, inspect condition of its financial condition through bank or authentic channel even. The indebted rate of the supplier had better not exceed 70% , indebted rate is exorbitant have bankrupt risk at any time. Besides the indebted rate that inspects a supplier and manufacturing situation, inspect the circulating fund condition of the supplier even. The enterprise with very difficult circulating fund, you ordered money to them, handed in imprest, but they make imprest move he is used, because this is caused,deliver the goods to procrastinate badly period, losing still is an user. 9, equipment of numerical control of principle of environmental protection safety also has flaw, slack, flat appearance, environment of this meeting pollution and create waste, should hold to a standard, strict requirement, to process material, if contain harmful to person material, should not exceed bid. Current, our country already began to undertake attestation of environmental protection standard to the enterprise, carry the business of this attestation, also should become the company of first choice when we order goods. The electric product of numerical control equipment complement often has safe demand, these products should reach safe level, best can pass safe attestation. 10, science checks and accept a principle to often discover a few enterprises, can buy numerical control equipment with high price, and do not agree to spend money to ask authoritative orgnaization to undertake character is checked and accept. Some foreign traders grasped this weak point, shoddy perhaps, the reject that perhaps gives out them gives Chinese user. And Chinese user did not undertake through authoritative orgnaization science is checked and accept strictly again, allow their deceive pass a test, also crossed period of claim for compensation when the user discovers, the result is dummy eats the rhizome of Chinese goldthread, suffering does not say. Besides what ask authoritative orgnaization to have science, outside be being checked and accept strictly, make clear the manufacturing spare parts that protocol experiments and batch even, so that assess the quality of numerical control equipment and craft adaptability on the spot. 11, the price of equipment of numerical control of performance/price ratio principle basically depends on the advanced sex of technical level, the stand or fall of quality and precision, the discretion of configuration and quality assure charge to wait. To numerical control the price of equipment must have integrated consideration, do not pursue low case blindly. But the cheat that also should prevent the price to go up, gave high price and did not buy good product; The equipment standard that perhaps buys, quality is good, but not worth however so much money, in result heart lopsided. Want serious ground goods to compare only, than product level, than quality, than configuration, than the function, than running cost, compare the price again finally, can buy the numerical control equipment with reasonable performance/price ratio. If pass the professional technology orgnaization that has reputation to undertake advisory acting, also be OK the choose and buy arrives of the numerical control equipment with reasonable performance/price ratio. Invite public bidding purchases the method of choose and buy that also should use goods to compare 3, but often cannot produce the decision of the mark of protocol a lot of index such as Wu of kimono of the structure that tastes a level, craft, quality try to quantify. Can list only in mark book a series of menu type index of assessment, the result wins the bid to will surely not acquire satisfactory product by low principle. Because this suggests, even if invite public bidding is purchased, also want to undertake reviewing bid according to the principle of performance/price ratio, do not go after low blindly and fall into the trap of low. CNC Milling