JPS598328B2 - Vacuum or pressure forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for trimming (molding) even if the molded product is thick or made of hard material in vacuum forming or pressure forming of thermoplastic materials. The purpose of the present invention is to make it possible to easily and efficiently perform edge finishing cutting by cutting off unnecessary edges of a piece of paper by hand using a manual blade such as a knife.

Conventionally, in the vacuum (pressure) molding method, trimming of molded products is difficult by hand with scissors or a knife when the wall thickness of the molded product is approximately 1 mm or more for hard molded products or approximately 3 ml or more for soft molded products. Therefore, in order to efficiently process a large amount of molded products, (c) A trimming die (cutting die) mechanism, which is generally a press method, is added to the vacuum (compressed air) molding equipment to process the material to be molded under vacuum. (Pneumatic) After molding and before removing it from the mold, the trimming die mechanism is operated to trim the molded product.

(2) Alternatively, a trimming die device is installed separately from the vacuum (pressure-pressure) forming device, and the molded product manufactured by the vacuum (pressure-pressure) forming device and not subjected to the tri-synching treatment is then processed by the trimming die device.

is considered normal. However, the addition of the trimming die mechanism (1) and the trimming die device (2) require quite high costs for the mold and equipment, so they are not suitable for mass production of the same molded product, but for small volume production. The burden of mold and equipment costs is large, which has a small impact on the cost of the molded product.

In addition, regarding (2), if the molded product is a large, soft and relatively stiff product, there is a drawback that handling it is << and resetting it to the trimming die device is surprisingly time consuming. Therefore, even if the molded product is thick or made of hard material, the present invention can easily and efficiently trim the molded product by hand using a manual cutter such as a knife. This eliminates the need for the trimming die mechanism (1) or (-Z trimming die device), which imposes a large burden on mold and equipment costs, in the case of small-volume production of molded products.
This allows molded products to be manufactured at low cost.

To explain in detail based on the illustrated example, 1 is a vacuum mold, 2 is a large number of vacuum holes opened in the molding surface, 3 is a vacuum chamber formed in the mold, and 4 is a vacuum mold for air in the vacuum chamber. Using a vacuum pipe to be removed, cover the mold 11FC with a heat-softened sheet thermoplastic material S according to a conventional method, and drain the air between the material S and the mold 1 from each vacuum hole 2 of the mold. By suctioning and displacing the material S, the material S is molded in close contact with the molding surface of the mold 1.

5 indicates a holding clamp for material S.

The mold set table, cooling pipe, vacuum pump, material heating device, etc. are omitted from the figure. In the present invention, a groove 6 (a first
, Fig. 2), or a groove 6 with a relatively narrow opening width (wide inside) (triangular cross-section in Figs. 4 and 5, circular cross-section in Fig. 6) is provided. A vacuum hole 61 is opened inside.

Then, according to a conventional method, the material S to be molded is applied to the mold 1 to perform molding of the material S, and at the same time, the air in the groove 6 is removed and the material portion S1 corresponding to the groove 6VC is drawn into the groove 6 to form the material S2. Then, the thickness of the material portion S1 is reduced by stretching the material and formed into a thin wall that can be easily cut with a manual cutter such as a knife.

In other words, when the material portion S is drawn and formed S2, the original thickness of the material S is changed so that the thickness of that portion changes to a thickness that can be easily cut with scissors and a manual cutter such as a knife due to the stretching of the material. Taking into consideration the opening width w, depth d of the groove 6,
Alternatively, the cross-sectional shape and size are set in advance. After removing the above-mentioned molded product from the mold 1, the thin-walled part S2 formed along the trimming line of the molded product is sandwiched as shown in Fig. 3, and cut with a manual cutter 7 such as a knife to remove unnecessary edges. The part is removed from the molded product side, and in this case, the molded product is thick,
Alternatively, even if the material is hard, the trimming line portion is formed into a thin wall S2 as described above, so a manual cutter 7 such as scissors can be used.
Trimming can be done easily and efficiently by hand.

Even if a groove 6 is formed with a narrow opening width w (undercut shape with a wide interior) as shown in Figs. Since the thickness is thin (and the rigidity is extremely small), the molding material portion fitted into the groove can be easily released from the mold without any problem.

In addition, in order to prevent the wall thickness of the effective molded product from becoming thinner due to the influence of drawing the material portion S1 into the groove 6 along the trimming line, the material S to be molded is first placed in the mold 1. After molding, the molded product is held in the mold 1 as it is, and before the molded product is cooled, the air in the groove 6 is removed, and the material portion S1 is drawn into the groove in a two-stage molding procedure. It's good to do that.

Figures 2, 5, and 6 show, for the purpose of two-stage molding, that the vacuum chamber 62 of the vacuum hole 61 that excludes the air in the groove 6 is replaced with the vacuum chamber 3 of the vacuum hole 2 that opens on the molding surface of the mold 1. is separately provided, and the material portion S corresponding to the groove 6 is drawn and molded by switching the vacuum pipe 63 on the vacuum chamber 62 side to 0 NVC immediately after molding the material S to be molded with the mold 1. .

Although the above description has been made using a vacuum forming mold as an example, the present invention can be similarly applied to a pressure forming method. That is, according to the present invention, even if the molded product is thick or made of hard material in the vacuum or pressure forming method, the molded product can be trimmed using scissors and a manual cutter 7 such as a knife. It can be easily and efficiently done by hand.

Also, depending on the shape of the molded product and the length of trimming, the same worker can perform trimming work at the same time as vacuum forming work. This method is effective and suitable as a molding method when no equipment is available.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a mold in which the trimming line portion of the molded product has been made thinner. Figure 2 is a cross-sectional view of a modified example of the same mold, and Figure 3 is a trimming molded with a thinner material. FIGS. 4 to 6 are diagrams showing examples of various cross-sectional shapes of grooves. 1 is a vacuum forming mold, 2 is a vacuum hole, 3 is a vacuum chamber, 4 is a vacuum pipe, 5 is a material clamp, 6 is a groove for forming a thin trimming part, 61 is a vacuum hole opened in the groove, and 62 is the same. A vacuum chamber of a vacuum hole, 63 a vacuum pipe opened into the vacuum chamber, S a material to be molded, S1 a trimming line material portion of a molded product to be formed into a thin wall, and S2 a thin molded portion thereof.

Claims (1)

[Claims] 1. In a vacuum or pressure forming method, an opening width W is relatively narrow and a depth d is deep along the trimming line at a position on the mold surface corresponding to the trimming line of the molded product, or A groove 6 having a cross-sectional shape with a relatively narrow opening width W and a wide interior is provided, and the material S to be molded is molded on the molding surface of the mold 1.
A vacuum or is a pressure forming method. 2 In the vacuum or pressure forming method, the opening width W is relatively narrow and the depth d is deep, or the opening width W is comparatively large along the trimming line at the mold surface position corresponding to the trimming line of the molded product. After forming a material S to be molded on the molding surface of the mold 1, the material portion S_1 corresponding to the groove 6 is inserted into the groove 6 before the molding material is cooled. A vacuum or pressure forming method characterized in that the thickness of the material portion S_1 is sandwiched by drawing and forming into a thin wall that can be easily cut with a manual cutter 7 such as a knife.