JP2006272558A - Horizontal molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a horizontal optical component molding machine which minimizes the lowering of axis alignment accuracy and other molding accuracy caused by inevitable temperature nonuniformity between parts. <P>SOLUTION: In the horizontal lens molding machine comprising a fixed platen 1 fitting a fixed mold 7, a rear part platen 3, upper and lower tie-bars 4 and 9 supported horizontally by the fixed platen 1 and the rear part platen 3, and a movable platen 5 which is supported slidably by the upper and lower tie-bars 4 and 9 and fits a movable mold 8, the fixed mold 7 and the movable mold 8 are clamped by the horizontal movement of the movable platen 5 along the upper and lower tie-bars 4 and 9. The fixed platen 1 is formed from a low expansion material with a linear expansion coefficient of 5×10<SP>-6</SP>/K or below. Preferably, the rear part platen 3, the movable platen 5, the upper and lower tie-bars 4 and 9 are formed from a low expansion material. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical component molding apparatus and method for molding an optical component using a mold. More specifically, it is a horizontal molding device that moves the mold horizontally, and horizontal optical component molding that improves the molding accuracy by preventing temperature differences between parts or misalignment due to fluctuations. It relates to the device.

  Conventionally, various molded products have been manufactured by injection molding using a mold. For example, Patent Document 1 discloses a method for forming a disk for an information recording medium and a forming machine therefor. The molding machine described in this document is generally configured as shown in FIG. In other words, this molding machine has a fixed platen 101 and a cylinder 103, and four tie bars 104 are installed horizontally between them. A movable platen 105 is slidably supported on the tie bar 104. The movable platen 105 is driven by a cylinder 103. A fixed mold 107 and a movable mold 108 are attached to the fixed platen 101 and the movable platen 105, respectively.

Then, with the movable mold 108 clamped to the fixed mold 107 by the cylinder 103, a resin material is supplied from the injection unit 111 to mold the disk. Here, the fixed mold 107 and the movable mold 108 are temperature-adjusted to be heated to the resin molding temperature.
Japanese Patent Laid-Open No. 10-323872

  However, when the above-described conventional molding machine is used for molding lenses and other optical components, there are the following problems. That is, in this type of molding machine, the temperature of the stationary platen 101 is also increased by the temperature of the stationary mold 107 being adjusted. For this reason, a difference in thermal expansion occurs between the fixed platen 101 and the cylinder 103. This becomes a factor causing an axial deviation between the fixed platen 101 and the movable platen 105. That is, the platen shaft is displaced between the fixed platen 101 and the movable platen 105. The platen axis is an axis on the platen that passes through the intersection of the diagonal lines of the four tie bars 104 and is perpendicular to the mold mounting surface of the platen.

  Further, the thermal expansion of the movable platen 105 due to the temperature adjustment of the movable mold 108 also causes an axis deviation. Further, the four tie bars 104 also tend to be hotter in the upper one than the lower one. This is because the air heated by the movable mold 108 and the fixed mold 107 goes upward. This reduces the parallelism between the fixed platen 101 and the movable platen 105. For these phenomena, it is possible to reduce the temperature non-uniformity by increasing the number of temperature control points, but it cannot be completely eliminated.

  The present invention has been made to solve the problems of the conventional molding machine described above. That is, an object of the present invention is to provide a horizontal optical component molding apparatus that suppresses as much as possible the axis misalignment between dies due to unavoidable temperature non-uniformity between the respective parts and other factors that lower the molding accuracy.

In order to solve this problem, the horizontal optical component molding apparatus of the present invention includes a fixed platen to which a fixed mold is attached, a rear platen, an upper tie bar and a lower tie bar that are horizontally supported by the fixed platen and the rear platen. , A movable platen that is movably supported between the fixed platen and the rear platen and attaches a movable mold, and the movable platen moves laterally along the upper tie bar and the lower tie bar so that the fixed mold and the movable mold are moved. The fixed platen is made of a low expansion material having a linear expansion coefficient of 5 × 10 ⁻⁶ / K or less. By doing so, axial misalignment between dies due to an inevitable temperature difference between the stationary platen and the rear platen is suppressed. This minimizes a decrease in molding accuracy.

  Furthermore, not only the stationary platen but also the rear platen and the movable platen should be made of a low expansion material. In addition, if the upper tie bar and the lower tie bar are also made of a low expansion material, a decrease in parallelism between molds can be suppressed.

  Examples of the low expansion material include 34 to 36% by weight of nickel, the balance being iron and inevitable impurities (so-called invar), 30 to 33% by weight of nickel, and 4 to 6% by weight of cobalt. Containing, the balance being iron and inevitable impurities (so-called super invar), 34-36 wt% nickel, 1-2.8 wt% silicon, and carbon content 2.4 wt% , Manganese content does not exceed 1% by weight, the balance is iron and inevitable impurities (so-called Ni-resist), 30 to 33% by weight nickel, 4 to 6% by weight cobalt, 0.8 Examples include those containing ˜3% by weight of carbon, 1 to 3% by weight of silicon, and 0.4 to 2% by weight of manganese, with the balance being iron and inevitable impurities (so-called novinite).

  INDUSTRIAL APPLICABILITY The present invention can be applied to a horizontal optical component molding apparatus of a tie bar support system in which a movable platen is slidably supported on an upper tie bar and a lower tie bar. Further, the present invention can also be applied to a frame-supporting horizontal optical component molding apparatus that includes a frame that supports the fixed platen and the rear platen, and the movable platen is slidably supported by the frame. Of course, it is possible to support the movable platen with both the tie bar and the frame.

  According to the present invention, there is provided a horizontal optical component molding apparatus that suppresses as much as possible a reduction in alignment accuracy and other molding accuracy due to inevitable temperature non-uniformity between portions.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the best mode for embodying the present invention will be described in detail with reference to the accompanying drawings. The present embodiment embodies the present invention as a lens molding apparatus for manufacturing a lens for a camera equipped with a mobile terminal.

  The lens molding apparatus of this embodiment is configured as shown in FIG. That is, the fixed platen 1 and the rear platen 3 are disposed on the frame 2. These platens are fixed to the frame 2. When these platens are viewed from the side in FIG. 1, they are almost square. An upper tie bar 4 and a lower tie bar 9 are installed between the fixed platen 1 and the rear platen 3. There are actually two upper tie bars 4 and two lower tie bars 9, which are arranged at the four corners of the stationary platen 1 and the rear platen 3. The upper tie bar 4 and the lower tie bar 9 are fixed to the fixed platen 1 and the rear platen 3 and are parallel to each other.

  A movable platen 5 is disposed between the fixed platen 1 and the rear platen 3. The movable platen 5 is substantially square when viewed from the side in FIG. 1, and the upper tie bar 4 and the lower tie bar 9 penetrate the vicinity of the four corners. A guide bush 51 is provided at a location where each tie bar passes through the movable platen 5. The clearance between the guide bush 51 and each tie bar is set to be as small as 3 μm. The movable platen 5 is slidable with respect to the upper tie bar 4 and the lower tie bar 9. The movable platen 5 is supported by the upper tie bar 4 and the lower tie bar 9 while floating from the frame 2. The rear platen 3 is provided with a hydraulic press 6. The hydraulic press 6 and the movable platen 5 are connected by a tie rod 61. That is, the hydraulic press 6 can be moved left and right in FIG.

  A fixed mold 7 is attached to the surface of the fixed platen 1 on the movable platen 5 side. An injection unit 11 is provided on the back side of the fixed platen 1. A movable mold 8 is attached to the surface of the fixed platen 1 on the movable platen 5 side. Here, the temperature of the movable mold 8 and the fixed mold 7 is adjusted by temperature adjusting means (not shown) such as an oil heater.

  In addition, the kind of molten resin to be used should just be described in Unexamined-Japanese-Patent No. 2004-144951, Unexamined-Japanese-Patent No. 2004-144953, and Unexamined-Japanese-Patent No. 2004-144554, for example.

  FIG. 1 shows a lens forming apparatus of a tie bar support type in which the load of the movable platen 5 is received by the upper tie bar 4 and the lower tie bar 9. The present invention can also be applied to a frame support type lens molding apparatus (FIGS. 2 and 3) that receives the load of the movable platen 5 at the frame 2.

The fixed platen 1 in the lens molding apparatus of this embodiment is made of a low expansion material having a linear expansion coefficient of 5 × 10 ⁻⁶ / K or less. Specifically, it is one of those shown in Table 1.

  In the lens molding apparatus of this embodiment configured as described above, the temperature of the fixed mold 7 and the movable mold 8 is adjusted. Specifically, it ensures the fluidity of the resin when the resin is filled into the mold and the temperature at which the resin cools and solidifies (generally, the glass transition temperature of the resin, the temperature near the heat distortion temperature below the crystallization temperature). The temperature is adjusted in the range up to room temperature. Molding is performed in that state. That is, the mold is clamped as shown in FIG. In this state, the molten resin is supplied from the injection unit 11 to the cavity between both molds to mold the lens.

  Here, as described above, the stationary platen 1 is made of a low expansion material. For this reason, even if there is a temperature difference between the fixed platen 1 and the rear platen 3 at the time of molding, the difference in thermal expansion between the fixed platen 1 and the rear platen 3 is small. Therefore, there is almost no axial deviation between the fixed mold 7 and the movable mold 8.

  This has the following advantages. First, the shape accuracy (surface accuracy, parallel accuracy of front and back surfaces, and eccentricity accuracy) of the molded lens is very high. This is because the axial alignment accuracy between the fixed mold 7 and the movable mold 8 is maintained high even in the temperature rise state. For this reason, it can respond also to a small-diameter lens for a camera mounted on a portable terminal or a pickup. Further, the sliding of the movable platen 5 is smooth even in the temperature rise state. This is because the parallelism of the upper tie bar 4 and the lower tie bar 9 is maintained. For this reason, even though the clearance between the guide bush 51 and each tie bar is set to be small, the movable platen 5 can slide smoothly even in the temperature rise state. This small clearance also contributes to the high molding accuracy of the lens.

If the fixed platen 1 is made of a material having a general linear expansion coefficient (about 12 × 10 ⁻⁶ / K), the state of each part is schematically shown in FIG. It becomes. That is, due to the difference in thermal expansion between the rear platen 3 and the fixed platen 1, the tie bar spacing differs between the platens. This is because the temperature rise of the rear platen 3 is slower than the temperature rise of the fixed platen 1 and the movable platen 5 and a temperature difference is likely to occur. Therefore, molding is performed in a state where the thermal expansion of the rear platen 3 is smaller than the thermal expansion of the stationary platen 1. For this reason, the upper tie bar 4 and the lower tie bar 9 are bent, and parallelism is also impaired. Further, as can be seen from FIG. 6 seen from above, the parallelism between the upper tie bars 4 is also impaired. The parallelism between the lower tie bars 9 is similarly harmed. Of course, FIG. 5 and FIG. 6 depict the deformation of each part in a considerably exaggerated manner. By using a low expansion material for the stationary platen 1, such an adverse effect can be eliminated.

  Furthermore, not only the stationary platen 1 but also the rear platen 3 and the movable platen 5 should be made of a low expansion material.

  Further, it is better if the upper tie bar 4 and the lower tie bar 9 are also made of a low expansion material. By doing in this way, the bad influence by the thermal expansion difference especially of the upper tie bar 4 and the lower tie bar 9 can be excluded.

  If each tie bar is not a low expansion material, the situation of each part at the time of molding will be the situation schematically shown in FIG. That is, due to the difference in thermal expansion between the upper tie bar 4 and the lower tie bar 9, the fixed platen 1 and the rear platen 3 are slightly inclined. For this reason, the parallelism between the fixed mold 7 and the movable mold 8 is lowered. For this reason, the shape accuracy (axial accuracy and parallel accuracy of the front and back surfaces) of the resulting lens is poor. Of course, FIG. 7 is a drawing exaggerating the deformation of each part.

  Further, the thermal expansion in the radial direction of the upper tie bar 4 and the lower tie bar 9 is large in the vicinity of the fixed platen 1 and the movable platen 5 and is small in the vicinity of the rear platen 3. The movable platen 5 cannot slide smoothly due to the non-uniformity in the longitudinal direction of the thermal expansion and the decrease in parallelism. The clearance between the guide bush 51 and each tie bar may be set large, but this further reduces the shape accuracy (the eccentric accuracy of the front and back surfaces).

  When a low expansion material is used for the upper tie bar 4 and the lower tie bar 9, the stationary platen 1 and the rear platen 3 are prevented from tilting even in a temperature rise state. Even if the upper tie bar 4 and the lower tie bar 9 have temperature non-uniformity in the longitudinal direction, the non-uniform tie bar diameter is insignificant.

  Hereinafter, measurement examples (including comparative examples) of the temperature and deformation state of each part will be described. First, in this measurement example, the temperature measurement location of each tie bar was set at an intermediate position between the fixed platen 1 and the movable platen 5. In addition, for the upper tie bar 4 on the operation side (the side where the operation unit is installed, usually the lower side in FIG. 6), the position near the rear platen 3 was also measured (hereinafter referred to as “X”). Indicated by). This is to grasp the temperature non-uniformity in the length direction in one tie bar.

  Table 2 shows the results of temperature measurement for each part. The unit of temperature is “° C.” (the same applies to Table 3 and below). The room temperature was 26 ° C. throughout the test. The mold temperature during molding (fixed mold 7 and movable mold 8) was 115 ° C., and the resin temperature in the injection unit 11 was 260 ° C. “Immediately after the temperature rise” means immediately after the fixed mold 7 and the movable mold 8 reach the molding temperature 115 ° C. The column “3 hours after the start of molding” is provided in Table 2 for about 3 hours after the fixed mold 7 and the movable mold 8 reach the molding temperature until the temperature of each part is generally stabilized. This is because of this. From this, 3 hours after the start of molding may be referred to as “molding initial stage”, and thereafter “after molding stability”.

  Thus, immediately after the temperature rise between the respective parts, the temperature difference (absolute value) at the initial stage of molding is calculated as shown in Table 3. In the table, “movable P”, “fixed P”, and “rear P” indicate the movable platen 5, the fixed platen 1, and the rear platen 3, respectively. “Between tie bars” indicates the maximum temperature difference between the upper tie bar 4 and the lower tie bar 5 in total. “Tie bar length” indicates a temperature difference between two temperature measuring points of the upper tie bar 4 on the operation side.

  From Table 3, it can be seen that there is a considerable temperature difference between the stationary platen 1 and the movable platen 5 and the rear platen 3. Similarly, there is a considerable temperature difference in the longitudinal direction of the tie bar. There is also a certain temperature difference between the fixed platen 1 and the movable platen 5. This is considered to be due to a difference in distance from the rear platen 3. There is also a certain temperature difference between the upper and lower tie bars. In addition, the column “Fluctuation of temperature difference” in Table 3 is the fluctuation range of the temperature difference of each part after molding stability. The temperature measurement results in Tables 2 and 3 were common to this embodiment and the comparative example.

  Next, the deformation state of each part in the comparative example (no low expansion material is used) will be described. At each stage of “immediately after temperature rise”, “initial stage of molding”, and “after stable molding”, between the fixed mold 7 and the movable mold 8, Table 4 (Comparative Example 1: Tie bar support type in FIG. 1) and The amount of shaft misalignment shown in the column of “axis misalignment” in Table 5 (Comparative Example 2: frame support type in FIG. 2) occurred. The “necessary C” column is a value obtained by experimentally obtaining a clearance necessary for the movable platen 5 to move smoothly in each stage. The column of “parallelism” indicates the degree of decrease in parallelism between the fixed platen 1 and the rear platen 3. The units of “axis deviation”, “necessary C”, and “parallelism” are all “μm” (the same applies to Table 6 and below). In Tables 4 and 5, both values are quite large (bad). Among these, “immediately after temperature rise” and “initial stage of molding” are due to the difference from the state before temperature rise. “After molding stability” is due to changes during molding.

On the other hand, in this embodiment, the results shown in Tables 6 to 8 were obtained. Here, the following types of lens forming apparatuses were tested in this embodiment.
Form 1: Tie bar support type of FIG. 1; Low expansion material (super invar) is used only for the fixed platen 1 Form 2: Tie bar support type of FIG. 1; fixed platen 1, rear platen 3, movable platen 5, upper tie bar 4 and the lower tie bar 9 are all made of low expansion material (super invar). This form 3: frame support type of FIG. 2; fixed platen 1, rear platen 3, movable platen 5, upper tie bar 4, and lower tie bar 9 All use low expansion material (Super Invar)

  In Tables 6 to 8, as compared with Tables 4 and 5, the axial deviation is approximately one-tenth of the value. From this result, it can be seen that the use of the low expansion material for the fixed platen 1 can significantly reduce the axial deviation and the decrease in parallelism. And in Table 7 and Table 8, the axial deviation especially after a shaping | molding start is still smaller. The parallelism is particularly excellent. These are the effects of using a low expansion material for the rear platen 3, the movable platen 5, the upper tie bar 4, and the lower tie bar 9 in addition to the fixed platen 1.

  As described in detail above, in the lens molding apparatus according to the present embodiment, a low expansion material is used for at least the stationary platen 1. Preferably, the movable platen 5, the rear platen 3, the upper tie bar 4, and the lower tie bar 9 are also made of a low expansion material. For this reason, even if there is a temperature difference between the parts when the temperature is raised to the molding temperature, the difference in thermal expansion between the parts is small. Therefore, the axial alignment between the fixed platen 1 and the movable platen 5 is good even during molding. The parallelism between the platens and the parallelism of each tie bar are also good. As a result, a lens molding apparatus is realized that suppresses as much as possible the deterioration of the alignment accuracy between the dies, the parallelism, and other molding accuracy due to inevitable temperature non-uniformity between the respective parts. Of course, the target is not limited to optical parts, but it can be used to form all parts with strict accuracy requirements for positional deviations.

  Note that this embodiment is merely an example, and does not limit the present invention. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof. For example, in the case of the frame support system shown in FIG. 2, a configuration with a support such as an LM guide may be used. The means for driving the movable platen 5 is not limited to a hydraulic press. Hydraulic cylinder system, hydraulic toggle system, electric motor cylinder system, electric motor toggle system, etc.

  Further, the target of temperature adjustment is not limited to the movable mold 8 and the fixed mold 7. The temperature of the rear platen 3, the upper tie bar 4, the lower tie bar 9, and the frame 2 may be adjusted. The temperature adjusting means is not limited to the oil heater, but may be a water circulation type or an electric heat exchange element type. The total number of tie bars is not limited to “4”.

It is a front view which shows the structure of the lens shaping | molding apparatus (tie bar support) which concerns on embodiment. It is a front view which shows the structure of the lens shaping | molding apparatus (frame support) which concerns on embodiment. It is AA sectional drawing which shows the structure of the lens shaping | molding apparatus (frame support) which concerns on embodiment. It is a front view which shows the condition at the time of shaping | molding. It is a schematic diagram (front view) which shows the condition of each part at the time of temperature rising in case a rear platen is not a low expansion material. It is a schematic diagram (plan view) showing the situation of each part at the time of temperature rise when the rear platen is not a low expansion material. It is a schematic diagram (front view) which shows the condition of each part at the time of temperature rising in case a tie bar is not a low expansion material. It is a conceptual diagram of the conventional injection molding machine.

Explanation of symbols

1 fixed platen 3 rear platen 4 upper tie bar 5 movable platen 9 lower tie bar

Claims (9)

A stationary platen for attaching a stationary mold, a rear platen, an upper tie bar and a lower tie bar supported laterally by the stationary platen and the rear platen, and a movable platen supported between the stationary platen and the rear platen. In a horizontal optical component molding apparatus, comprising: a movable platen to which a movable mold is attached, wherein the movable platen moves sideways along the upper tie bar and the lower tie bar to clamp the fixed mold and the movable mold. ,
The horizontal optical component molding apparatus, wherein the fixed platen is made of a low expansion material having a linear expansion coefficient of 5 × 10 ⁻⁶ / K or less. The horizontal optical component molding apparatus according to claim 1,
The horizontal optical component molding apparatus, wherein the rear platen and the movable platen are also made of a low expansion material having a linear expansion coefficient of 5 × 10 ⁻⁶ / K or less. In the horizontal optical component molding apparatus according to claim 1 or 2,
The horizontal optical component molding apparatus, wherein the upper tie bar and the lower tie bar are also made of a low expansion material having a linear expansion coefficient of 5 × 10 ⁻⁶ / K or less. In the horizontal optical component molding apparatus according to any one of claims 1 to 3,
The low-expansion material contains 34 to 36% by weight of nickel, and the balance is iron and inevitable impurities. In the horizontal optical component molding apparatus according to any one of claims 1 to 3,
The low-expansion material contains 30 to 33% by weight of nickel and 4 to 6% by weight of cobalt, and the balance is iron and inevitable impurities. In the horizontal optical component molding apparatus according to any one of claims 1 to 3,
The low expansion material contains 34 to 36 wt% nickel and 1 to 2.8 wt% silicon, the carbon content does not exceed 2.4 wt%, and the manganese content is 1 wt%. A horizontal optical component molding apparatus characterized in that the remainder is iron and inevitable impurities. In the horizontal optical component molding apparatus according to any one of claims 1 to 3,
The low expansion material comprises 30 to 33 wt% nickel, 4 to 6 wt% cobalt, 0.8 to 3 wt% carbon, 1 to 3 wt% silicon, and 0.4 to 2 wt%. A horizontal optical component molding apparatus characterized in that it contains 1% manganese and the balance is iron and inevitable impurities. In the horizontal optical component molding apparatus according to any one of claims 1 to 7,
The horizontal optical component molding apparatus, wherein the movable platen is slidably supported by the upper tie bar and the lower tie bar. In the horizontal optical component molding apparatus according to any one of claims 1 to 7,
A frame that supports the stationary platen and the rear platen;
The horizontal optical component molding apparatus, wherein the movable platen is slidably supported by the frame.

Images