JPS6038251B2 - electroforming cavity - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coin cavity used in plastic molding.

Conventional electroplating materials for open casting cavities are mostly nickel plating, with some nickel alloy platings being put into practical use.

The internal surface hardness of these is not very high for molding cavities, and with electrolytic nickel plating, HV280~35
0. Even electrolytic nickel alloy plating that has been put into practical use has a hardness of HV50 at most. Therefore, there is a drawback that accidents such as abrasion or scratching of the internal surface easily occur during molding. Furthermore, since the method is based on electroplating, the charge concentration on the protrusions during the initial stage of plating on the master results in poor coverage and the occurrence of dendrites, which causes many operational problems. Furthermore, due to the high adhesion of electroplating, there was a drawback that the master could not be pulled out without careful mold release treatment. In order to eliminate these drawbacks of the prior art, the present applicant has previously filed an application for an electrolytic nickel plated or electrolytic nickel alloy plated bell cavity characterized by having an electroless nickel plating layer on the inner surface. Electroless nickel plating is H for phosphorus-based plating.
V450 is higher than HV750 and electrolytic nickel plating in the case of boron-based plating, and is suitable as the inner surface material of the exposed key cavity. However, whether this electroless nickel plating is phosphorus-based or boron-based, the plating thickness is only 10 to 20 plating per hour. Furthermore, as the thickness increases, the surface becomes more uneven and the internal strain increases. Therefore, if only one layer of electroless sealing is applied to the inner surface of the capacitor, the thickness will not be sufficient, and its hardness will not be utilized against high loads. In order to eliminate these drawbacks, the present invention forms an electroless nickel plating layer on the inner surface of the cavity, and below that, multiple layers of electrolytic nickel plating and electroless nickel plating are formed alternately, and an electrolytic nickel plating layer is formed as the final layer. It is something.

With such a structure, the electroless nickel plating layer on the inner surface of the cavity is stronger than the inner layer, and a decrease in hardness can be prevented.

Next, examples will be described.

Brass, carbon steel, stainless steel, aluminum, plastic, and the like are used as the material for the master for manufacturing the gun space.

A desired shape, for example a gear, is formed at one end of this master. First, electroless nickel plating is applied to this master. Composition as an example of phosphorus-based electroless nickel plating: Nickel chloride 30 minutes/Sodium hypophosphite 30 minutes/Soda acetate
Plating was carried out for 3 hours at 12 m/s surfactant and 0.2 m/s 70 oz to obtain a plating thickness of 20 mm.

This is the inner surface (first layer) of the completed dewy cavity.
This is the result. Next, electrolytic nickel plating is applied to this master, composition: nickel sulfamate 6
002/nickel chloride 5/boric acid
A plating layer (second layer) having a thickness of 0.2 mm was formed using polyethylene glycol of 10 mm/sleeve and 6,000 ml of polyethylene glycol for 1 hour.

Furthermore, on top of this, as a boron-based nickel electronic key lock, composition: Nickel sulfate 50%/lactic acid
20 evening/sodium citrate
25 Tanok dimethylaminoborane 2.5 treble/Thiothiodiglycolic acid 1.5 Tanok ammonia 7 Tanok 60-7000 in 2 hours, 15 treps thick plating layer (
3rd layer) was formed.

Finally, using the solution with which the second layer was electroplated, 30A
Plating was performed at 60 qo/dm2 for 2 feeding hours to form a plating layer (fourth layer) with a thickness of about 3 skins.

As shown in the figure, "The first layer 1 is an electroless nickel plating layer on the outside of master A, the second layer 2 is an electroless nickel plating layer on the outside, and the third layer 3 is an electroless nickel plating layer on the outside. A fourth electrolytic nickel plating layer is formed on the outermost layer.

A cavity B is formed by the first layer 1 to the fourth layer 4,
This can be released from the master A to obtain a cavity. As another example, the master is first electroless nickel plated with composition: nickel chloride.
10 evenings/soethylenediamine 30 evenings/mekasei soda 20 evenings/sodium borohydride 0.5 evenings/sleeve 5000,
The treatment was carried out for 2 hours to form a first layer of boron-nickel electroless coating having a thickness of 20y.

Next, as a second layer, bright electrolytic nickel plating was performed for one hour to obtain a thickness of 5 mm. Furthermore, as a third layer, the composition is: Nickel sulfate 30 minutes / Sodium phosphate 10 days / Potassium citrate
It was treated with ammonium sulfate for 2 hours at 90 to 95 qC for 2 hours to form a phosphorous nickel electroless glazing layer of about 15 mm.

Finally, electrolytic nickel plating was performed using nickel sulfamate to form a fourth layer with a thickness of 5 to form a cavity.
When this cavity was compared with a cavity using a single electroless glazing layer, it was found that the hardness was improved by 20% and the durability was significantly increased. In the above two embodiments, four layers are formed in each case, but the number of layers can be set as appropriate depending on the layer thickness and the like.

Naturally, the higher the degree of adhesion between the electroless coating layer and the electroplating layer, the better, so it is better to work between each layer in a short period of time, while leaving water leaking from the surface of the object to be plated. Ta.

[Brief explanation of drawings]

The drawing is an explanatory cross-sectional view of one embodiment of the present invention.

Claims (1)

[Claims] 1. An electroformed cavity in which an electroless nickel plating layer is formed on the surface of the recess, and a plurality of electric nickel plating layers and electroless nickel plating layers are alternately formed, and an electric nickel plating layer is formed as the final layer.