T/F mould designs a technology
- source:WILK CNC Machining
It Also Analyzes The Related Calculation Methods.
As the development of semiconductor technology, product of integrated circuit of the DIP of domestic tradition, SIP is replaced by the product place such as SOP, QFP, SSOP, TSOP gradually, traditional hand is moved strong cut shape the craft requirement that the mould already cannot satisfy high density, much down-lead to count IC product, because this rushs automatically,cut shape system (Trim/Form System) it is the working procedure after integrated circuit rushs cut shape the development trend of equipment, be sure market of rapid and occupational China. T/F mould is T/F develops the core share that cuts a system, the design method that grasps T/F pattern is very important. The working procedure after T/F mould designs point integrated circuit is strong cut shape to have anything resembling a tendon or vein of glue of strong runner incomplete, strong model, hit the point commonly, shape beforehand, shape, the working procedure such as depart, working procedure combination chooses according to goods characteristic. Below the design point that waits for a respect to elaborate T/F mould from analysis of the nucleus of school of the design that discharge appearance, intensity, strong computation that reduce force, structure. The design that discharge appearance seals product figure and client to produce according to model can ask, affirmatory working procedure is combined and rush every time cut a product several, step pitch size and mould dimension are cut into parts to determine mould amount according to rushing when discharging appearance. If step pitch of product down-lead frame is small, whole shapes when precision demand is not high, can use a pair of class to take a pattern, use two pairs otherwise or combination of third mate mould. When two pairs of moulds, general the first pair completes process of muscle of glue of strong runner incomplete, hit the point; Mould of second mate is finished shape beforehand, shape, the working procedure such as depart, the consideration is convenient next makings (enter a canal or enter dish) , pattern of depart of third mate can raise on foundation of two pairs of moulds. Computation of sunken model intensity develops as the high speed of microelectronics technology, integrated circuit forward the way of much down-lead, small span develops, be like QFP176L, down-lead step pitch only 0.
4mm, when be being designed must intensity of mature sunken model. Foregone (see a picture 1, graph 2) : B -- sunken model width (2 abdicate part) , mmH -- sunken model height, mmI -- the key of carry on one's shoulder of sunken model, mmt -- down-lead frame ply, mmW -- of down-lead frame cut off width, mm δ F -- the cutting of down-lead frame stress, kg/mm2 criterion: The point ministry of sunken model the F of δ of P=2tW getting power of each place (Kg) what load nods add in sunken model to curve torque M=PI (Kgmm) the susceptive of section coefficient sunken model of sunken model curves susceptive of sunken model of stress δ B to cut decision criteria of stress δ Snextpage: Intensity of sunken model of contented and the following formula must satisfy afore-mentioned decision criteria at the same time. The choice mould of bedspring of makings of list of performance of material of horniness aluminium alloy the bedspring force on discharge board with the discharge when combining a model board place gets active force, and send makings slideway place to suffer the element such as active force to concern, the experiment proves, the bedspring force on discharge board is taken about 0.
The pattern of 4 times is strong reduce force, namely: The mould of bedspring force ＝ on discharge board develops the × that reduce force 0.
4: = of every bedspring load can choose bedspring accordingly according to bedspring force, the fatigue intensity of demand spring should be achieved 1 million times. The estimation of angle of spring back of the product that make a turn pursues 3 in θ 1, the 2 regulations that to shape the product pursues are worth θ . Shape sunken model shapes the computation of R (see a picture 4) NextpageRc -- R1 of radius of line of the center after product spring back -- product figure tags dimension Ra -- Rs of diameter of line of the center before spring back -- hit curved sunken model to shape R θ 1 -- product icon notes size, when strong runner, because connect muscle place not to have sunken model point, if rush at the same time with down-lead casing,cut, cut even muscle part ceaseless, stay easily in model to seal body to go up, because this punch should be designed,be shape of a flight of stairs, rush first cut runner and even muscle, fullback cuts down-lead casing. T/F mould uses a curve to hit curved means to be opposite as the market the demand of the product is higher and higher, traditional tigidity hits a turn to shape means can make abrade of layer of product surface tin-plating serious, cannot satisfy higher and higher product exterior demand, because this T/F mould uses a curve to make curved way, its ideal curve is shown 6 times like the graph. If the graph is shown 7 times,the curve makes curved structure. This is CAM makes curved way, its job principle, it is to add up to modular nowadays model to prop up piece urge construction of upper mould CAM, gyro wheel begins to roll on CAM curve, begin to rotate for fulcrum with fulcrum axis, make punch head hits bent housing leg to shape thereby, such product surface abrade are small, bent appearance is stable. Anyhow, the design rationality of T/F mould affects the character of the product and stability directly. Its design a technology is to rush automatically cut shape crucial technology of the system, we are will ceaseless advancement, excelsior, the pattern with complete, strong versatility serves design function at using person. CNC Milling