CN1086861A

CN1086861A - Manufacturing method of precision parts of sewing machine

Info

Publication number: CN1086861A
Application number: CN 92112646
Authority: CN
Inventors: 林汉水; 陈炎山
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-11-11
Filing date: 1992-11-11
Publication date: 1994-05-18

Abstract

A method for manufacturing precision parts of sewing machine comprises forming into blank by dewaxing casting method in precision casting, and processing; firstly, polystyrene is subjected to injection molding and die-casting molding to form a wax mold, then dipped with zirconium sand for several times to serve as a pre-coated layer, the wax mold is put into an electric furnace to melt plastic wax to form a hollow zirconium sand mold, the hollow zirconium sand mold is sintered to form a ceramic mold, and then a casting procedure is carried out to enable metal molten slurry used by precision parts to be cast in the zirconium sand mold to form a primary blank; after the primary blank is finished, welding, processing matching surface and heat treatment are carried out, and then the surface and the fine part are ground to precisely grind the outer edge.

Description

The method for making of precision parts of sewing machine

The present invention relates to a kind of method for making of precision parts of sewing machine, it is to be wax-pattern with the lost-wax process in the hot investment casting with high temperature wax injection moulding, is stained with and soaks zircon sand to take off high temperature wax, is shaped to germule through the sintering casting cycle; After germule is finished, weld, process mating surface and heat treatment, grind again and thin portion precise finiss, the size block of precision component finished product is formatted with this method for making.

Sewing machines except be provided with the sewing needle set that can wear suture at needle stand, also must be at shuttle in the needle stand bottom side assembling and be furnished be nested with in the precision components such as outer sleeve body of shuttle, below be that example explains with middle shuttle:

In the prior art Sewing machines used middle shuttle as shown in Figure 6, with in the central shaft 45 of shuttle 4 wear another line tube, whereby the suture of line tube is worn the hole to the anvil block; In the form of shuttle 4 be one as cut half of oval hollow body, form around the body internal surface have top and bottom revolve veneer 41, in 42 all sides of supporting surface of end face limit 43 and lower end projection one outer rim 46 again, line tip 44 is colluded in the formation of end in addition of outer rim 46.

The technical process of shuttle 4 is shown in the schematic flow sheet of Fig. 7 in the manufacturing of prior art, it at first is block near middle shuttle 4 with the steel bar forging molding, initial processing outer shape and size, cut off the half block body, turning then, milling hollows out inner excess stock, with form become arc surface up and down revolve veneer 41, preliminary milling tip and breach, and male and fomale(M﹠F) and collude the line tip, again boring and milling in shuttle 4 surfaces and plurality of holes, preliminary then turnning and milling outer rim 46 and collude line tip 44, revolve veneer 41, collude line tip 44, at this moment positions such as outer rim 46 reach size more accurately in the finishing mode of manual milling, weld central shaft 45 again, the processing that eliminates stress, turning mating surface and chamfering, the heat treatment hardened surface, follow above-mentioned position and carry out the precise finiss processing of thin portion (grind mating surface, gloss grinds and the line tip is colluded in reconditioning), obtain finished product.The method for making of above-mentioned prior art has a lot of shortcomings.

Wherein, steel bar forging molding in advance is a block, outside turning processing back cuts off half block body shape, in the turning of half shape block inside, milling hollows out to form revolves veneer 41, this program is because the regular shape of the easy clamping of the non-instrument of middle shuttle 4 body shape institute, add and revolve veneer 41 and roll off the production line that sliding to draw edge 47 be a complicated cambered surface, thereby the procedure that hollows out is extremely many, be difficult for reaching accurate dimensions and radian, two-end thickness very easily takes place, the inhomogenous phenomenon of radian, the processing percent defective is quite high, even the scratch of process tool obviously as seen, cause that to revolve veneer 41 surface smoothness bad, the line tube that easily causes reclining with this face produces the phenomenon that rubs greatly and have rotation to have some setbacks when turn, and hollow out processing and expend a lot of materials, processing capacity is big, cutter very easily fast weares and teares, and processing number and process equipment are many, make material, increase cutter apparatus cost and process time several times in rain, moreover hollow out inner method, make that none calibration of whole machine-shaping is accurate, processing capacity is big, yielding and cutter loss causes performance accuracy to differ, so the dimensional weight of shuttle 4 differs in each, the overall weight inequality, easily when the assembling running, balance and stability are bad, and it is unitized more can't to reach part, and quality is very different; In addition, because middle shuttle 4 must be noted the dimensional accuracy of outer rim 46, with the sharp inclined-plane accuracy and the relative angle that collude line tip 44, thereby often when initial processing, the phenomenon that very easily makes mistakes makes that follow-up attrition process is difficult to carry out smoothly, must increase the program of finishing earlier.If process with the computer-controlled process equipment of high precision, because cost is higher, practicality and applicability are all undesirable.

Another kind of manufacture is shown in Fig. 8 schematic flow sheet, after going out two steel materials, after three bending formings, remove unnecessary material, with two steel plate welding fabrications, in the middle of middle shuttle 4 relative outer rims 46, be pre-formed two parts up and down, be end face limit 43 with supporting surface 42 respectively after the moulding again the precompressed seam becomes integral body, preliminary then milling tip and breach, and male and fomale(M﹠F) and collude the line tip carry out hand finish, weld central shaft 45 again, the processing that eliminates stress, turning mating surface and chamfering, heat treatment hardened surface and attrition process (are ground mating surface, gloss grinds and the line tip is colluded in reconditioning) etc. a plurality of programs, obtain finished product.Know by inference thus, above-mentioned method for making must be used many process equipments and craft in each manufacturing technique, and after the completion of processing, still can not reach parts standardization, the shape of shuttle 4, size all can't be standardized in each, cause the difficulty of producer on the assembling Sewing machines, spent cost can't reach due value of the product on producing, especially middle shuttle 4 is to establish and with the power driven rotary for the line jacket casing, it is the state that often is in contact friction, substantial connection is to the parts of Sewing machines performance, so for producing and function own, truly have improved necessity.

Main purpose of the present invention is: a kind of method for making of precision parts of sewing machine is provided, and it is shaped to germule with the lost-wax process in the hot investment casting, and reprocessing forms precision component; Earlier polystyrene being injected die cast is wax-pattern, is stained with then and soaks zircon sand for several times, forms the zircon sand mould and fuses wax, carries out sintering again, to form ceramic die, carries out the casting program then, makes the used molten metal casting of precision component be shaped to germule in model; After germule is finished, welding, finish turning finished surface and heat treatment are ground and thin portion correct grinding finishing outer rim again.Be pre-formed as germule earlier with this microcast process, make the ground moulding of global shape polishing, many procedures have been reduced, can directly grind, repair, overcome prior art to hollow out or accessory size that method for making such as pressure welding combination causes and the shortcoming that thickness is inaccurate, precision is not high, to make the precision component homogeneous that produces and accurately, reduced procedure greatly, the rate of reducing the number of rejects and seconds rationally and is effectively enhanced productivity.

The invention provides a kind of method for making of precision parts of sewing machine, it is characterized in that: the casting of plastics wax injection pressure is shaped to the plastics wax-pattern, being stained with dip-coating smears and forms for several times the coating of precoating, to become model after the wax dissolving, put into sintering furnace again and carry out sintering, the molten metal casting that precision component is used is shaped to germule in model;

After finishing, tentatively grinds germule, welding, and the processing mating surface, mating surface and thin portion precise finiss outer rim are ground in heat treatment.

The method for making of aforesaid precision parts of sewing machine is characterized in that available polystyrene blended wax is as the used wax-pattern of lost-wax process.

The method for making of aforesaid precision parts of sewing machine, the coating that it is characterized in that precoating can be the zircon sand slurry, after the wax dissolving, form ceramic die.

Further specify architectural feature of the present invention and purpose below in conjunction with accompanying drawing.

Brief Description Of Drawings:

Fig. 1 is the process flow diagram of germule of the present invention.

Fig. 2 is a schematic diagram of fabrication technology of the present invention.

Fig. 3 is the outside drawing of the first embryo forming of middle shuttle of method for making of the present invention.

The outside drawing of the middle shuttle that Fig. 4 makes for method for making of the present invention.

The middle shuttle plane that Fig. 5 makes for method for making of the present invention.

Fig. 6 is the outside drawing of the middle shuttle of prior art.

Fig. 7 (hollows out inner method for making for the middle shuttle schematic diagram of fabrication technology of prior art.）

Fig. 8 is middle shuttle schematic diagram of fabrication technology (two welding method for makings of another prior art.）

Please referring to Fig. 1, Fig. 2, the present invention utilizes procedures such as finish turning grinding and finishing can reach the middle normalized purpose of shuttle mainly with fusiformis shape in the microcast process moulding in advance then; Owing to polystyrene is not out of shape because ambient temperature reaches to move to clash into, the manufacturing of the precision component that the utmost point is suitable for approaching, at first utilize polystyrene plastics wax injection pressure to cast from and be shaped to the plastics wax-pattern in the metal die, with the high temperature spatula dozens of high temperature wax die welding is located in the wax flow path system then, make the plastics wax-pattern be stained with the slurry dip-coating and precoat coating for several times, the coating of precoating of the present invention promptly be for zircon sand slurry (be the zircon sand paste of exotic material, the industry claims that this program is for being stained with slurry), put into sinter box after the dewaxing again, 1000 ℃ of temperature, carry out sintering under 30 fens clock times, to form ceramic model, carry out the casting program again, at this moment that middle shuttle is used SNCM-21 molten metal casting is shaped to germule 1 in model, as shown in Figure 3.

After germule 1 is finished, its male and fomale(M﹠F) shape, angle, the completion morphology of shuttle during quite approach most advanced and sophisticated and position, then carry out manufacturing skill (please cooperate Fig. 4) shown in Figure 2, because this is with the cast molding of high temperature wax model, so surperficial luminosity is smooth near the plane, almost reach the standard that needs, can directly establish central shaft 23 in supporting surface 25 welderings of middle shuttle 2, process mating surface then and meet the requirements of size, carrying out surface hardening again handles, then carry out precise finiss and gloss polish process, shuttle 2 each face reach more accurate angle and size in making, please cooperate referring to Fig. 5, carry out thin portion precise finiss and finishing program at last, to outer rim 22 end A partly, B, C ora terminalis everywhere carries out the part and grinds reaching accurate dimension, and makes perpendicularity and levelness between each ora terminalis also can reach standard, line most advanced and sophisticated 24 and the most advanced and sophisticated part of finishing are colluded in grinding, and shown in Figure 4 is the finished product outward appearance.

Advantage of the present invention is as described below:

1. utilized the lost-wax process in the hot investment casting. This is to utilize the wax-pattern injection-moulding plastic, and this wax-pattern is firm and not yielding, can have suitable precision, is germule 1 with the in advance cast molding of middle shuttle 2, carries out the processing technologys such as finish turning grinding and heat treatment again. Because middle shuttle 2 is irregularly shaped, each surperficial radian, angle and position are neither identical, and the cambered surface smoothness that especially revolves veneer 21 is difficult for reaching, and abrasive machining apparatus often is difficult for stretching in the narrow breach with refacing. But after the hot investment casting moulding with lost-wax process, its smooth surface, so need not process and expend a lot of materials, even lip-deep concavo-convex, hole and breach size, shape partly can be processed again, thereby middle shuttle 2 is after germule 1 is finished, revolve veneer 21 and namely reached the polishing form, do not need hand finish and consume material, effectively overcome in the prior art and to hollow out out-of-flatness, variable thickness that processing causes with car, milling etc. and cause and waste the shortcoming such as man-hour.

2. owing to use the hot investment casting moulding, the form of middle shuttle 2 is determined by model, make it standardization, unitized, and required processing capacity is few, middle shuttle 2 quality that produce are unified and accuracy is splendid, avoid the in the past very different phenomenon of product, greatly improve the quality of products, reduce the artificial and equipment cost of making.

3. can process simultaneously more than the dozens of with the lost wax casting manufacturing process, make processing cost low, the production efficiency height need not increase many process equipments, has improved utilization rate of equipment and installations, has breakthrough development.

4. because the germule 1 that hot investment casting forms has had quite complete Form, thus do not need the skilled filing that manually gives, and with coated abrasive working etc. can not homogenization processing technology, manufacturing process is controlled easily, the precision of product is good.

Claims

1. A method for making precision parts of sewing machines, which is characterized in that: plastic wax is injected and molded into a plastic wax mold, and then dipped and applied several times to pre-coat the coating, the wax is dissolved to form a mold, and then put into a sintering furnace Carry out sintering, and cast the molten metal used for precision parts into the mold to form the embryo;

After the initial embryo is completed and initially ground, welding, machining of the mating surface, heat treatment, grinding of the mating surface and detailed precision grinding of the outer edge are carried out.

2. The method for manufacturing precision parts of sewing machines according to claim 1, characterized in that polystyrene mixed wax is used as the wax pattern used in the dewaxing method.

3. The manufacturing method of precision sewing machine parts according to claim 1, characterized in that the pre-coating layer is zirconium mortar, which is sintered to form a ceramic mold after the wax is dissolved.