CN1236584A - Technology for manufacturing bimetal coins. - Google Patents

Abstract

A technology for manufacturing bimetal coins features use of two metallic band materials with different colours but same thickness as raw materials and use of the external ring and internal core to be combined for forming one coil. It includes such technological steps as punching the external rings and internal cores with each metal band to obtain two kinds of external rings of different metals and two kinds of internal cores of different metals, making flange on the edge of external ring, making a central groove on cylindrical surface of internal core, and pressing them together to form a bimetal coin. Its advantages are saving raw material by more than 25%, high bounding power between ring and core, simple process and low cost.

Description

The production method of bimetallic coin

The present invention is the production method of a kind of bimetallic coin, commemorative coin (chapter), medal.

From the eighties, the rise of the inflation and the coinage prices of raw and semifnished materials makes many countries begin the production of high denomination of coin successively.But the diameter of coin can not be simply along with the increase of the face amount of coin and increase, can only otherwise distinguish, and high par value coin needs certain novelty and antifalsification, for this reason, some countries have just begun the development of bimetallic coin.China is since the research of the early 1990s bimetal coin, all carrying out a large amount of technical research and engineer testing aspect gold and silver coin and Huang, the copper-nickel alloy circulation coin, and introducing part producing equipment.

Bimetallic coin, bimetallic souvenir badge, medal etc. with two parts metal of unlike material through impressing chimeric making, the bimetal coin of various countries, bimetallic souvenir badge all comprise an outer shroud and an inner core usually, but concrete chimeric mode and production technology but has nothing in common with each other.Chinese patent prospectus CN1112818A discloses the method for the bimetal coin of a kind of Korea S production, Canadian Patent and European patent have also been quoted in this specification simultaneously, their common feature is that the punching out of inner core and outer shroud is carried out respectively, and the thickness of the used band of inner core and outer shroud is different, therefore for making a kind of bimetallic coin, its stock utilization is all lower, especially the sheet metal strip of punching out outer shroud, bore diameter of outer ring can only be as how much waste materials with the blanking of lining, stock utilization only is that the comprehensive utilization ratio of 40.55%, two kind of material also only is about 52%.In addition, outer shroud and inner core are combined into one by impression, so just exist the possibility of disengaging, both bond strengths directly affect the prestige and the service life of product, in order to make both in conjunction with firmly, mostly make groove or oncus etc. making on oncus or the inner cylinder face on the cylinder of the garden of inner core at outer shroud.Process on the inner cylinder face of outer shroud, the technology more complicated is processed oncus on the face of cylinder of inner core, need to strengthen the thickness of inner core, make slit that excess metal flows to faying face to strengthen adhesion, therefore existing process is complex process not only, and the waste of material is unavoidable.

The objective of the invention is to propose a kind of production method of new bimetallic coin, it both can improve the adhesion of inner core and outer shroud, can save material and reach the requirement that increases product variety again.

Method of the present invention is: select two kinds of color and luster differences for use but the identical sheet metal strip of thickness, and the method that adopts outer shroud and inner core cover to use, punching out goes out the outer shroud base cake of two kinds of metals, and the core material that the outer shroud of punching out simultaneously falls becomes two kinds of metal inner core base cakes; When the base cake was carried out limit portion and Surface Machining, planar circumferential place and the upper and lower circumference of outer shroud place all processed flange about inner core, processed a circle groove at middle part, the inner core face of cylinder; With the inner core of the outer shroud of two kinds of metals and the two kinds of metals suit that intermeshes, be embossed into two kinds of double-colored metal coin again.

Its outer shroud manufacturing procedure is stamping-out, rolling, annealing, surface treatment, becomes outer shroud.

Its inner core manufacturing procedure is that the interior material that the stamping-out outer shroud falls becomes inner core through annealing, surface treatment, rolling.

The rolling amount of inner core can reach 0.33mm.

Inner core and outer shroud in conjunction with after, the upper and lower surface in the junction leaves transition platform.

Advantage of the present invention: owing to adopt the metal material of two kinds of uniform thickness to make outer shroud and inner core, the core material that a kind of outer shroud of punching out is fallen can be made the inner core of another kind of bimetal coin, has therefore saved raw material in a large number, and has increased the kind of double-colored metal coin; Because the circumference of inner core is made flange, during impression, very fast core, the czermak space of having filled of the part of flange closes closely core, loops, and the slit is little; And the surface of finished product coin still kept a transition platform, when making inner core combine impression with outer shroud, held part metals, guaranteed the space of faying face groove, the outer shroud metal flowed in the groove of inner core with comparalive ease, thereby make both combinations securely; Owing to the processing to inner core has changed traditional process, the rolling operation is moved at last carry out again, the processing capacity when having guaranteed rolling can increase to requirement, and processing capacity quite conventional method is big, but can not influence processing quality; Owing to the increase of rolling amount, the work-hardening capacity of limit portion increases simultaneously, and this makes groove only produce less distortion in moulding process and guarantees that enough space admittance outer shroud metals are arranged.Of the present invention method is simple, with low cost, remarkably productive.

Details of the present invention provides by following examples and accompanying drawing thereof:

Fig. 1 is the bimetal coin structural representation that the inventive method is produced.

Fig. 2 is the outer shroud structure chart among Fig. 1.

Fig. 3 is the core arrangement figure among Fig. 1.

Fig. 4 impresses preceding state diagram among the inner core among Fig. 1 falls into outer shroud.

Fig. 5～8th, moulding process schematic diagram of the present invention.

Fig. 9 is the marker map that outer shroud and inner core are cut out a piece of cloth in a way with the minimum material to make two or more articles of clothing among the present invention.

Figure 10 is a core czermak space profile of the present invention.

Figure 11 is a minimum clearance enlarged drawing among Figure 10.

Figure 12 is a maximal clearance enlarged drawing among Figure 10.

With reference to the accompanying drawings 9, this example requires finished product external diameter 25.5mm, inner core diameter 17.5mm, the thick 19.5mm in limit.

Method of the present invention is to adopt outer shroud and inner core to cut out a piece of cloth in a way with the minimum material to make two or more articles of clothing, and at first choose two kinds of sheet metal strips: copper-nickel alloy and brass, both thickness is identical.Strip width 1=174mm, be vertical row's 10 row towards tool, horizontally-arranged 8 row, interior edge-lapped value b=1.2mm, outer edge-lapped value is a=2.5mm, and outer shroud and inner core overlap the time spent mutually, calculates the stamping-out yield rate and reaches 76.91%, and total stamping-out yield rate of independent punching out outer shroud and independent punching out inner core is 51.94～51.75%, and stock utilization of the present invention exceeds more than 25%.

Be of a size of external diameter 24.45 ± 0.03mm through cutting out a piece of cloth in a way with the minimum material to make two or more articles of clothing two kinds of outer shroud base cakes that punching out comes out, internal diameter 17.50 ± 0.03mm, ring base cake is of a size of external diameter 17.65 ± 0.03mm, thick 1.80 ± 00.040mm to thick 1.80 ± 00.040mm in two kinds that punching out comes out through cutting out a piece of cloth in a way with the minimum material to make two or more articles of clothing.

From above base cake size as can be known, cut out a piece of cloth in a way with the minimum material to make two or more articles of clothing owing to adopt, the internal diameter of outer shroud and inner core outside dimension are basic identical (because there are the gap in punch and die, cause inner core in the internal diameter of external diameter and outer shroud difference slightly), and in conjunction with outer shroud and inner core the time, need suitable gap, inner core could successfully fall among the outer shroud in high-speed and continuous processing.Therefore the rolling amount in the inner core processing is bigger than conventional method.

1-4 with reference to the accompanying drawings: outer shroud base cake is carried out plain edge, annealing, surface treatment make outer shroud 1 on edge knurling machine; The outer shroud of being made 1 is of a size of: external diameter 25.33 ± 0.03mm, and internal diameter 〉=17.45mm, thickness 1.80mm, the above and below outward flange has flange 2.

With inner core base cake anneal earlier, surface treatment, carry out rolling at last and make inner core 3; The inner core of being made 3 is of a size of: external diameter 17.32 ± 0.04mm, thickness 1.80mm.In rolling, by the bent plate on the edge knurling machine groove 5 is made at the middle part, the face of cylinder of inner core, make flange 4 at the edge of top and bottom, the processing capacity of rolling is 0.33mm.

This method places the plain edge operation of inner core at last, has broken conventional manufacturing procedure, and its purpose is exactly to make the rolling operation that bigger processing capacity can be arranged, and the unlikely surface-treated quality that influences.Because if operation was carried out rolling, when the rolling amount is big before surface treatment routinely, can form very steep edge, place, slope at the internal orifice place of flange root, the annealing back forms oxide skin, is difficult to again during polishing be ground to, stay the dark-coloured vestige of a circle, influence the surface effect of finished product.

5-8 the inner core 3 of brass put in the copper-nickel alloy outer shroud 1 with reference to the accompanying drawings, on printing machine, impress; Equally the inner core 3 of copper-nickel alloy is placed the outer shroud 1 of brass, on printing machine, be embossed into bimetal coin.Be shaped on groove 9 that holds transition platform 6 and the groove 10 that holds outer ring flange 2 on the patrix 7 of impressing mould, the counterdie 8.Upper and lower mould 7 and 8 first centers again around extrusion metal, make metal flow, by mold shape connecting shaping gradually.

The finished size that impresses out is: external diameter 25.5mm, inner core diameter 17.50mm, the thick 1.95mm in limit (flange).Outer shroud combines firmly with inner core in the finished product.The reason that improves adhesion is: 1. on the coin face except that impressing out decorative pattern, transition platform is left in joint portion at two kinds of metals, it is this transition platform has held inner core in moulding process part metals, thereby reserved enough spaces for groove 5, this just makes the outer shroud metal be filled to as much as possible in the groove 5.Obviously, the metal of outer shroud 1 filling in inner core groove 5 is many more, and shearing force required during separation is just big more.2. because the rolling amount reaches 0.33mm, much larger than prior art, make limit portion metal hardenability big, groove has higher intensity, and this has guaranteed that groove is out of shape in moulding process less, kept shape preferably, makes the outer shroud metal be easy to flow into.3. be that inner core limit portion deformed area concentrates on flange portion, this part metal is out of shape soon during impression, is filled to core, czermak space place rapidly, and when the bulk deformation amount is very little, just the gap is filled up, and core circumferential weld crack is reduced.According to the slit profile shown in Figure 10-12, press P among the figure ₁-P _1RMeter between 2, maximum slit is 0.016mm, minimum slit is 0.003mm, and disclosed joint slit is 0.08mm to the maximum in the korean patent application (CN1112818A), minimum is 0.03mm, and core circumferential weld of the present invention crack is its 1/5～1/10, thereby adhesion strengthens.Through this routine adhesion of separating experiment is 5312N, surpasses the about 2000N of prior art.

Claims (4)

1, the production method of bimetallic coin, it is characterized in that: select two kinds of color and lusters differences for use but thick identical sheet metal strip, the method that adopts outer shroud and inner core cover to use, punching out goes out the outer shroud base cake of two kinds of metals, and the core material that the outer shroud of punching out simultaneously falls becomes two kinds of metal inner core base cakes; When the base cake was carried out limit portion and Surface Machining, planar circumferential place and the upper and lower circumference of outer shroud place all processed flange about inner core, processed a circle groove at middle part, the inner core face of cylinder; With the inner core of the outer shroud of two kinds of metals and the two kinds of metals suit that intermeshes, be embossed into two kinds of double-colored metal coin again.

2, method according to claim 1, it is characterized in that: its outer shroud manufacturing procedure is stamping-out, rolling, annealing, surface treatment, becomes outer shroud, and its inner core manufacturing procedure is that the interior material that the stamping-out outer shroud falls becomes inner core through annealing, surface treatment, rolling.

3, method according to claim 1 is characterized in that: the rolling amount of inner core can reach 0.33mm.

4, method according to claim 1 is characterized in that: after inner core and the outer shroud combination, leave transition platform in the upper and lower surface that connects seam crossing.

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