JPH11211634A - Plastic test piece punching device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily obtain a test piece in an accurate punching shape without any crack and cut-out by allowing both of a punching blade holding part and a sample stand to incorporate a heater. SOLUTION: Since it takes time for the upper surface of a sample to be heated in the case of a heating method only from the lower surface of the sample due to heat transfer from a heated sample stand 2, punching machining is made while the upper surface of the sample is not heated in quick heating, so that the generation of crack and cut-out cannot be effectively prevented. On the other hand, in a heating method only from an upper surface, since the upper surface of the sample where a punching blade 31 hits is directly heated for effective operation by preventing crack and cut-out from being generated. In this manner, since a heating method from the upper surface of the sample is effective, heating from a lower surface can also be omitted. However, it is desirable that heating from the lower surface should be used together to prevent the warpage deformation of the sample due to the heating of a single surface. The heating from the upper surface is made without any contact due to radiation heat transfer from a heated punching blade retention part 3 and the punching blade 31, thus enabling an electric heating heater to be easily handled as a built-in heater.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for punching plastic test pieces.

[0002]

2. Description of the Related Art In order to conduct a tensile test or the like of a plastic material, a test piece having a predetermined shape (for example, in accordance with JIS tensile test method) must be punched out from an original sample. In some cases, pellets of 2 to 3 mm square are required for measuring the melt viscosity of the material.

Since the measured values of these test pieces are compared under a reference shape, it is necessary that their dimensions and shapes are accurate. Also, even if there are minute chips or scratches, stress concentrates there and breaks etc. occur with a force smaller than the normal value,
Inaccurate measurements cannot be obtained. Conventionally, when an original sample is a brittle material such as a hard plastic, cracking or chipping tends to occur when a test piece is prepared by a punching machine, and it has been difficult in some cases to prepare a test piece having an accurate size and shape.

In preparing pellets for measuring melt viscosity and the like, thick plastic sheets are manually cut with a guillotine cutter and scissors. However, there is a problem that labor is large and work efficiency is low. Was.

[0005]

The problem to be solved by the present invention is to provide a sample stage on which a plastic sample is placed and fixed, a punching blade for punching a test piece of a predetermined shape from the plastic sample, and a punching blade. In a plastic test piece punching device having a punching blade holding unit that holds and moves up and down for a punching operation, even if a plastic sample as a raw material is a brittle and fragile material such as a high-filled hard plastic, cracking or chipping occurs. An object of the present invention is to provide a plastic test piece punching apparatus capable of easily obtaining a test piece having an accurate punching shape without causing any problem.

[0006]

The above object can be attained by heating the punching blade holding portion of the plastic test piece punching device, or both the punching blade holding portion and the sample stage with a built-in heater.

That is, the present invention provides a sample stage on which a plastic sample is placed and fixed, a punching blade for punching a test piece of a predetermined shape from the plastic sample, and a vertical movement for holding the punching blade and performing a punching operation. A plastic test piece punching device, comprising: a punching blade holding portion for causing a plastic test piece to be punched out, wherein the punching blade holding portion, or both the punching blade holding portion and the sample stage, incorporate a heater. Is what you do.

According to the present invention, the heat from the punching blade holder heated by the built-in heater, or from both the punching blade holder and the sample stage, is transmitted to the plastic sample as the raw material, and the temperature rises to increase flexibility. As a result, even a brittle and fragile material such as a highly filled hard plastic can easily obtain a test piece having an accurate punched shape without cracking or chipping.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention is a method for heating a plastic sample. There are three heating methods for the plastic sample: only the upper surface, only the lower surface, and both upper and lower surfaces. Although the two-sided heating is the most excellent, according to the experience of the present inventors, it takes time until the upper surface of the sample is heated in the heating method from only the lower surface of the sample by the heat transfer from the heated sample stage. If the heating is performed for a short time, the punching process is performed while the upper surface of the sample is in an unheated state.

On the other hand, the heating method only from the upper surface is as follows.
Since the upper surface of the sample hitting the punching blade is directly heated, it works effectively by preventing the occurrence of cracks and chips. As described above, since the heating method from the upper surface of the sample is effective, it is possible to omit the heating from the lower surface.However, in order to prevent the sample from warping and deforming due to single-sided heating, the heating from the lower surface may be used together. desirable.

The heating from the upper surface of the sample is performed in a non-contact manner mainly by radiant heat transfer from the heated punching blade holder and the punching blade. When the punching blade comes into contact with the sample, contact heat transfer also occurs, but the effect is considered to be secondary because of the short time. As the built-in heater, an electric heater is preferable in terms of easy handling.

The present invention is intended to prevent the occurrence of cracks and chips by heating a plastic sample prior to punching a test piece to increase its flexibility. It should be noted that the effect of the processing history of the sample may be lost and a new heat history may be added. In general, the thermal expansion of a metal stamping blade is relatively larger than that of a plastic sample, so that when the punched test piece is cooled to room temperature, its dimensions are within the range specified in the test method. Care must be taken to enter. Therefore, it is desirable to determine an appropriate heating temperature and heating time experimentally and to perform accurate temperature and time management.

According to another embodiment of the present invention, there is provided a punching apparatus for a plastic test piece, which can rotate a sample stage by an arbitrary angle in a horizontal plane and translate the sample stage by an arbitrary distance from an initial position. Can be mentioned.

That is, in the present embodiment, the function of rotating and moving the sample stage is added to the plastic test piece punching apparatus of the present invention. The rotation function of the sample stage is realized by enabling the sample stage to rotate and fix around a support shaft that stands upright below the center. Also, the translation function
This can be realized by interposing a feed screw between the apparatus base and the upper part of the sample table including the support shaft. The front-back direction is practical as the direction of the parallel movement. The most practical rotation angle is 90 degrees, but the rotation angle may be, for example, 30 degrees or 45 degrees. It is desirable that the parallel movement distance can be directly read by a scale, and it is more desirable that the parallel movement distance can be digitally displayed.

As described above, when measuring the melt viscosity of a plastic material or the like, it may be necessary to prepare pellets of 2 to 3 mm square. According to the present embodiment, such pellets can be efficiently prepared.
That is, a punching blade having a plurality of linear parallel blades is attached to the punching blade holding unit, and a plurality of strips having a predetermined width are cut out from the target plastic sample by using a parallel movement function of the sample table. What is necessary is just to fix to a sample stand and to cut out a pellet using the rotation and parallel movement function of a sample stand. Also in this case, the heating function of the plastic test piece punching device of the present invention makes it possible to easily produce a pellet having a uniform shape without chipping or cracking from a hard and brittle material.

The present embodiment is useful not only for producing pellets but also for producing certain kinds of test pieces. In other words, a plastic material having anisotropy has different physical properties such as tensile strength depending on a cutting direction of the test piece. However, if the rotation function of the sample stage in the present embodiment is used, a test piece having an accurate direction can be easily obtained. Can be created.

As still another embodiment of the present invention, two push button switches for punching down the punching blade are arranged at the front of the apparatus with a space between both arms of a person, and the two push button switches are connected in series. And a plastic test piece punching apparatus.

This embodiment has significance as a safety measure in the plastic test piece punching device of the present invention. That is, the punching blade does not descend unless two push button switches provided on the front surface of the apparatus are simultaneously pressed with both hands, so that it is possible to prevent a finger injury accident common to this type of apparatus. As a further safety measure, it is desirable to cover the front and side surfaces of the device with a transparent acrylic plate or the like to protect the operator from flying debris in the event of a flying accident.

[0019]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a front view of a plastic test piece punching apparatus (reference numeral 1) according to the present embodiment. In FIG. 1, reference numeral 2 denotes a sample stage, 21 denotes a sample holder, 22 denotes a sample stage heater, 23 denotes a rotating plate, 24 denotes a 90-degree rotation handle, 25 denotes a slide plate, 26 denotes a translation handle,
27 is a moving distance scale, 3 is a punching blade holder, 3
1 is a punching blade, 32 is a punching blade holder, 33 is a heater for a punching blade holding unit, 34 is a relay terminal for a heater, reference numeral 4 is a drive unit, 41 is a power cylinder, 42 is a mounting unit, 43 is a limiter, and reference numeral 5 Is a base unit, and 51 and 51 are push button switches.

The sample stage heater 22 and the punching blade holder heater 33 are electric heaters, and include a thermocouple (not shown), and are controlled by a temperature controller (not shown) to maintain a predetermined temperature. Push button switch 5
Reference numerals 1 and 51 are provided on the front surface of the base 5 at a distance of about the distance between both arms of a person.
As long as you do not press 1, 51 with both hands at the same time, power cylinder 4
1 is wired so as not to operate.

A method of using the plastic test piece punching apparatus 1 configured as described above will be described.

A plastic sample sheet formed into a sheet having a predetermined thickness and cut to a required size is held by a sample holder 21 and fixed to the upper surface of the sample table 2. Further, a punching blade 31 for giving a desired punching shape is attached to the punching blade holder 32.

By pressing the push button switches 51, 51, the punching blade holder 3 is lowered, and the height thereof is adjusted to the punching blade 31.
Is adjusted to the height just before touching the plastic sample on the sample stage 2. Further, the 90 ° rotation handle 24 and the parallel movement handle 26 are moved to appropriately adjust the positional relationship between the punching blade 31 and the plastic sample.

In this state, the sample stage heater 22 and the punching blade holding unit heater 33 are energized to maintain the sample stage 2 and the punching blade holding unit 3 at a predetermined temperature for a predetermined time according to the properties of the plastic sample.

When the predetermined heating time has elapsed, the heater 2
The power supply to 2 and 33 is stopped, and the push button switches 51 and 51 are immediately pressed to further lower the punching blade holding unit 3, and the punching blade 31 is bitten into the plastic sample on the sample table 2 to obtain a desired shape. Make a test piece.

In the case of producing pellets, after the punching blade 31 is once pulled up, the sample stage 2 is rotated by 90 degrees, and a punching operation is further performed.

After the above punching operation is completed, the completed test piece is taken out of the apparatus 1.

Using the plastic test piece punching apparatus 1 of this embodiment, three types of plastic samples "PVC" and "P"
An experiment was conducted in which a test piece was actually prepared from MMA "and" PS ", and the results are described.

These three types of plastic samples are made of polyvinyl chloride (PVC) and polymethyl methacrylate (P
MMA) or polystyrene (PS) was compounded under the blending conditions shown in Table 1 to form a sheet under the roll conditions shown in Table 1.
It was prepared by pressing under the conditions described in (1). All have the property of being brittle and easily chipped due to high filling.

[Table 1]

A 200.times.200.times.3 (mm) sheet was prepared from the above-mentioned plastic sample by press molding, a JIS K 7113 No. 1 test piece punching blade was attached to the punching blade holder 32 of the apparatus 1, and the room temperature (23 ° C.) ) And under heating (80 ° C. on both upper and lower surfaces). The punching under heating was performed after the plastic sample was fixed and the sample table 2 and the punching blade holder 3 were maintained at 80 ° C. for 15 minutes. As a result, a test piece having a satisfactory shape without any chipping or cracking could be obtained under heating, but cracking occurred in "PVC" by punching at room temperature, and "PMMA" and "PS" has broken.

The plastic test piece punching apparatus 1 may be modified as follows. First, the temperatures of the sample stage heater 22 and the punching blade holder heater 33 can be adjusted independently. Second,
A coil spring slightly longer than the blade height of the punching blade 31 is attached to the lower surface of the punching blade holder 32 in the vertical direction.

While the heat from the punching blade holder 3 is transmitted to the plastic sample in a non-contact manner by radiant heat transfer,
Since the heat from the sample stage 2 is directly transmitted to the plastic sample by contact heat transfer, it is desirable to keep the punching blade holder 3 at a slightly higher temperature than the sample stage 2 in order to balance the heat transfer from both. Therefore, it is convenient if both temperatures can be controlled independently. This is the reason for the first change.

After the punching operation is completed, it is necessary to raise the punching blade 31. At this time, the test pieces and pellets separated from the plastic sample adhere to the punching blade 31 and rise together, and remove them from the punching blade 31. May be required. If a coil spring is attached to the lower surface of the punching blade holder 32 as in the second modification, the test piece or the like is automatically removed from the punching blade 31, which is convenient.

[0035]

According to the first aspect of the present invention, even when the plastic sample as a raw material is a brittle and fragile material such as a high-filled hard plastic, a test for an accurate punched shape without cracking or chipping occurs. Provided is a plastic test piece punching device that can easily obtain a test piece.

According to the second aspect of the present invention, there is provided a plastic test piece punching apparatus capable of efficiently producing pellets required for measuring a melt viscosity of a plastic material or the like.

[Brief description of the drawings]

FIG. 1 is a front view of a plastic test piece punching apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Punching apparatus of a plastic test piece 2 ... Sample table 21 ... Sample holder 22 ... Sample table heater 23
... Rotating plate 24 ... 90-degree rotation handle 25 ... Slide plate 26 ... Parallel movement handle 27 ... Movement distance scale 3 ... Punching blade holder 31 ... Punching blade 32 ... Punching blade holder 33 ... Punching blade holder heater 34 ... Heater Relay terminal 4 ... Drive unit 41 ... Power cylinder 42 ... Mounting unit 43 ... Limiter 5 ... Base unit 51 ... Push button switch

Claims (2)

[Claims] 1. A sample table for mounting and fixing a plastic sample, a punching blade for punching a test piece of a predetermined shape from the plastic sample, and a punching blade for holding the punching blade and moving up and down for a punching operation. A plastic test piece punching apparatus, comprising: a holding section; and wherein the punching blade holding section, or both the punching blade holding section and the sample stage, incorporate a heater. 2. A plastic test piece punching apparatus according to claim 1, wherein said sample stage can be rotated by an arbitrary angle in a horizontal plane, and said sample stage can be translated by an arbitrary distance from an initial position.