FI112455B - Process and plant for processing workpieces in a manufacturing process - Google Patents

Description

112455

The present invention relates to a method and apparatus for facilitating the processing of mass-produced workpieces in a process whereby the workpieces are formed into a fluid or viscous material. The invention relates to a process and apparatus for processing workpieces in a fluid or viscous material. This patent application contemplates injection molding as an exemplary manufacturing process. A workpiece is generally referred to as a workpiece during a process that forms the product at the end of the process.

Moving workpieces between work stages is often a problem in production automation. Much of the early industrial production was based on the conveyor belt and its more sophisticated forms, in which a particular conveyor moves separate semi-finished workpieces from one part of the production building to another. Naturally, this solution does not work in a very narrow area. Batch production technology produces a number of products at a time, which are placed in a batch frame, a jig, where they can be transported through various stages of work and / or from one stage to another. Placing workpieces in and out of the jig and moving the jig in this case are unproductive steps. In addition, in batch manufacture, the same work step, such as plating, is performed in the same way on all workpieces in the same batch frame, and individual processing of the products is not possible except by removing the desired individual workpieces from the jig.

,,! FI patent application 963873 discloses a manufacturing method and apparatus in which: semi-finished workpieces are connected in series and possibly in parallel niitä; 25 through connecting brackets. Figure 1 illustrates how the workpieces 1 produced by a certain manufacturing step form a long continuous strip which is wound onto a roll 4. It is conceivable in the example of the figure that the raw material used is injection-molded plastic and the articles 1 to be manufactured are small plastic articles. To avoid successive pieces, the jaws of the press of Figure 3 are shaped such that; There is a small amount left at the "end" of each workpiece (the right end in the picture): a plastic tongue, which is extraordinary to the intended shape of the product. Next. ,,; similarly, when a workpiece is injected into its "upstream end" (left end in the figure), a small plastic tab is formed, which is extraordinary to the intended shape of the article and melts into the tongue 35 of the previous workpiece end. Between successive workpieces a base 2 is formed which is of the same material as the workpieces themselves.

112455 2

Figure 2 shows a surface treatment belonging to the same manufacturing process. The strip of workpieces is brought to the surface treatment by roll 6. The workpieces are guided as a strip into a submerged basin 7 and then into a surface spraying 8 and a drying machine 9. Other exemplary surface treatment steps illustrated by FIG. two options are presented as a final step. According to the first alternative, the laser cutter 13 separates the workpieces from the strip 15, after which they must be treated as individual pieces in general. Alternatively, the finished workpieces are further wound onto a roll 14 or scooped into a stack, whereby they can be easily transported and placed in the assembly stage of a more complex product.

However, the prior art method described above has been found to be difficult in practice because it is difficult to control the flow of injection-molded plastic in the mold so precisely that the heels are formed as desired. In addition, the heels 15 often leave an unwanted mark on the edge of the workpiece.

Methods of forming a strip of successive workpieces and employing reinforcements of a non-solidizable material are known, for example, from U.S. Patent Nos. 5,478,051, 4,008,302 and 3,192,298.

JP 51-109062 discloses a method in which a successive workpiece 20 is formed into a band using two reinforcements and in which the material to be solidified is introduced at a point between the two reinforcements.

;;; It is an object of the present invention to provide an improved method and apparatus for manufacturing workpieces such that successive and / or parallel workpiece pieces form a preferred strip for further processing.

The objects of the invention are achieved by utilizing it in the manufacture of a workpiece:. a part formed in the step which is extraordinary to the final shape of the product. Some may comprise so-called. A "sprue", "git" formed as the material solidifies into the duct through which the fluid or viscous material is guided to desired locations in the mold. The part may also comprise a support wire or film which •; · '30 adheres to the solidifying material during or immediately after solidification.

. In the process of the invention i. - successive workpieces, after solidification of the material, form a band,. ·. ; - said tape comprises a reinforcement consisting of a non-stiffening material to improve the mechanical strength of the tape; and 112455 3 - two longitudinal reinforcements of said tape are used and the solidified material is introduced at a point between the two reinforcements; the method being characterized in that each workpiece comprises at least two utility pieces such that the point at which the material to be solidified is fed is located between the utility pieces.

The invention also relates to an apparatus for treating workpieces in a manufacturing process comprising forming individual workpieces by solidifying a liquid or viscous material, comprising means for forming a tape from successive workpieces, . The apparatus is characterized in that it comprises means for forming at least two payloads in each workpiece such that the point at which the material to be solidified is fed is located between the payloads.

15 In manufacturing processes based on solidification of a liquid or viscous material, it is typical that the material is guided to desired locations in the mold. through the drainage channel (s). In the solidification step, the material is still present in the ducts, whereby this part of the material is formed into so-called. jööti. The actual workpiece and the yoke are interconnected by a thin base of material at the point where the 20 ducts are in contact with the actual workpiece mold. Jute is often utilized in workpiece finishing because, for example, surface finishes that are intended to apply to the entire workpiece surface are easily accomplished by holding the '1' to the jute.

',,; According to a first embodiment of the invention, successive workpieces are attached ;;; 25, so that the workpiece per se is not attached to each other, but the yoke associated with each workpiece is connected to the workpiece of the previous and next workpiece. * 'Yes. According to this embodiment, the workpiece leaves no trace of the strip-like treatment other than that of the thin heel that would otherwise remain at the point where the workpiece and the jig were joined.

According to another embodiment of the invention, the yoke associated with each workpiece is associated with the yoke of the previous and subsequent workpiece by mechanically reinforcing the junction "" junctions, which passes through the jute. The wire prevents accidental breakage of the workpiece and jute tape. bend '35 repeatedly and / or have a large bending angle.

112455 4

According to a third embodiment of the invention, the reinforcing wire is partially retained within the workpiece. This embodiment can also be applied in connection with the previously known method of FI application 963873, whereby the reinforcing wire would pass directly from one workpiece to another. However, in the most preferred embodiment of the invention, the reinforcing wire passes between the workpiece and the associated jute. The part of the reinforcing wire remaining inside the workpiece can later be removed or left inside the workpiece.

According to a fourth embodiment of the invention, a film of flexible material is used which is permanently bonded to each workpiece so that a portion of the film remains in the final product. The film may be used, for example, to form the color and / or pattern of the product. With the help of a film strip, the workpieces are transported through certain stages of the manufacturing process which require smooth processing.

The invention will now be described in more detail with reference to exemplary preferred embodiments and the accompanying drawings, in which Figure 1 illustrates a prior art manufacturing process, Figure 2 illustrates a prior art process, Figure 3 illustrates a process of the invention, Figure 4 illustrates another process of the invention, Figure 5 illustrates another variation of the procedure of Figure 4, Figure 6 illustrates another variation of the procedure of Figure 4,. Figure 7 illustrates a combination of prior art procedures,: · Figure 8 illustrates another combination of prior art, Figure 9 illustrates an alternative embodiment of the invention, and. Figure 10 illustrates one way of utilizing a reinforcing wire.

With reference to the prior art, reference is made to Figures 1 and 2, so the following •. In the description of the invention and its preferred embodiments, reference is made mainly to Figures 3 -10. In the pictures, the same reference numerals are used for like parts.

Figure 3 illustrates a portion of a belt 300 comprising successive workpieces 301. Here, it is assumed that the workpieces are small molded moldings; the manufacturing method or material or the size of the workpieces are not relevant to the invention as such. By way of example, it can be assumed that the workpieces are intended to be made into "lenses" on the screen of a mobile phone, i.e., transparent, plate-like and slightly curved portions that are approximately 5,112 µm in size on a matchbox lid and glued to a screen otherwise opaque. Each workpiece is associated with a yoke 302 formed as the injection-molded plastic material solidifies into the duct. Depending on the size and shape of the workpiece, the yoke attaches to the workpiece with a thin stud at number 53. The studs may be multiple and may be disposed on different parts of the workpiece. According to the invention, the yokes of successive workpieces are connected to each other by a flexible heel at position 304. This heel is most preferably created in the same manufacturing step as the yoke. This can be done, for example, by a method similar to that described above for the connection of successive injection molded workpieces according to the prior art.

After the strip of successive workpieces and rocks as shown in Figure 3 has been passed through all the work stages that favor the strip-like shape, the workpieces are removed from the strip. There are two options for the removal process. 15 The first possibility is to cut off only the joints between the joints 304. In this case the workpieces become separate, but each piece still has a yoke that can be retained at a later stage. The yoke is then cut off from the workpiece. Another possibility is to directly cut the heels 303 between the rivets and the workpieces, so that the workpieces, after being removed from the 20 strips, get their final shape. The jute material typically ends up in re-melting and hence back to the beginning of the process.

.: Figure 4 shows a variation of the solution shown in Figure 3. Fig. 4 shows:: firstly, two bases 401 and 402 between each workpiece and its associated jitter, which is not in itself essential for the invention. A more significant difference from the embodiment shown in Fig. 3: ': 25 is the reinforcing wire 403, which runs uniformly:'; ': through all the rocks. The reinforcing wire 403 may be copper or other metal, something:. monofilament yarn, such as nylon string, or multifilament yarn, such as cotton, polyester, or mixed yarn, or any other braiding, such as nylon braid or kevlar braid. It may also be an elastic thread, such as an elastic band. If the reinforcing wire is; 30 meltable materials, its melting point must be higher than the melting point of the material used for injection molding. In the manufacturing process, the reinforcing wire is • drawn from the roll and inserted into the mold so that it remains inside the spinner during injection molding. As its name suggests, the reinforcing wire strengthens the joints between the joints, i.e. it has to withstand tensile and repetitive bending substantially better than the one made from injection-molded material. It is assumed in Fig. 4 that, despite the reinforcing wire, the Jieses are also interconnected by the heel of the injection molding material. This is not essential to the invention, but was jerking 6

I I L ·. v_ / sJ

can be completely separate so that they are joined at 304 by a mere reinforcing wire.

Figure 5 shows another variation of the solution of Figure 3. In this case too, a reinforcing wire is used, but now the wire does not pass between the ropes, but each workpiece 301 and its associated rope 302 are interconnected by a short reinforcing wire portion 501. The successive junctions are interconnected via pins 304. An advantage of the embodiment 3 is that the workpiece does not inadvertently disengage from the yoke or warp in an undesirable position relative to the yoke even if the base 303 is very thin. The thickness of the carrier 303 is then only determined by the fact that the injection-molded plastic must be able to flow into the mold at the desired speed. In Figure 5, reinforcing wire 501 is most preferably made of a relatively rigid material such as metal. It may be inserted into the mold prior to injection molding, whereby the material to be injected must flow into the mold at the side of the reinforcing wire, or it may be inserted into the hole connecting the duct and the actual mold immediately after injection molding.

Figure 6 shows a modification of the solution of Figure 5. In this embodiment too, the workpiece 301 and the rope 302 are interconnected by a piece of reinforcing wire 501, but it does not pass at the same point where the injection molding material flows from the casting channel 20 to the actual mold. There are two (401 and 402) two latter points, thus forming a thin plastic cap, as in Figure 4. The advantage of the embodiment of Figure 6 - is that the reinforcing wire can be inserted into the mold before injection and still does not interfere with the flow of material into the duct. : between the actual mold.

Figure 7 shows a possible combination of the principles shown in Figures 4 and 5. Figure 7 employs two reinforcing yarns, the first of which reinforcing yarn 403 runs between the rivers, thereby applying the same definitions as described above with respect to the embodiment of Figure 4. In addition, each workpiece and its associated •: jig are connected by a short piece of reinforcing wire 501, which corresponds to the 30 reinforcing yarns shown in Figure 5. In this embodiment, the reinforcing yarns may be of different material:. . For example, reinforcing wire 403 made of Kevlar fiber and reinforcing wire 501 copper wire.

. · ·. This is advantageous because the reinforcing wire 403 must withstand, in particular, tensile and repetitive, large bending, whereas the function of the reinforcing wire 501 is essentially to hold the workpiece in jute and prevent it from bending to undesirable positions.

Figure 8 shows a possible combination of the principles shown in Figures 4 and 6. In this embodiment, a single reinforcing yarn 801 is used which connects both the punctured rails and each workpiece-runner pair. In each jute, the reinforcing wire makes a bend whose extreme point extends to the workpiece side. This embodiment has the particular advantage that the manufacturing apparatus becomes simpler than in the embodiment of Figure 7, since the apparatus does not have to handle one continuous yarn and another yarn used as a piece. The invention does not limit how long the reinforcing wire passes through the workpiece or what kind of bends it makes inside the workpiece.

Of course, the embodiments of Figures 4, 5 and 6 may also be combined in other ways than those shown in Figures 7 and 8. For example, the unified reinforcing wire 10 of Figure 8 may pass through the heel (or joints) connecting the yoke to the workpiece.

Injection molding is sometimes referred to as so-called. hot duct, which means that the material does not solidify into the duct and thus does not freeze. In this case, those embodiments of the invention based on the exploitation of rocks cannot be applied. Fig. 9 shows a strip 900 of successive workpieces in which dashed lines indicate where the yoke would be if the hot duct was not used. The idea of using a reinforcing wire can be applied to join workpieces into a continuous strip. The figure shows two reinforcing blades 901 and 902 passing through each workpiece, thereby binding the workpiece 20 into a band. The number and position of the reinforcing wires relative to the workpieces are not essential to the invention. Between successive workpieces, there is no disclosure of similar heels used in the method according to FI patent application 963873, but the invention does not exclude the possibility of using such. In the method of Figure 9, the reinforcement wire is subject to the same requirements as in the embodiment of Figure 4, so that the same instructions as above apply to the selection of its material: ':':

For those embodiments in which one or more reinforcing wires passes through a workpiece, it is necessary to consider what is to be done to the reinforcing wire after it is no longer needed for its original purpose. The reinforcing wire will either be left on the finished ... · 30 product or disconnected in one way or another. Submission of the finished product; '· ,; comes mainly when it does not cause visual harm: the product is intentional. '. made such that its appearance is irrelevant, the material to be extruded is opaque or the reinforcing wire passes through a portion of the product which is subsequently dyed or otherwise covered so that the reinforcing wire is not visible. 35 For example, the edge portion of a cellular telephone lens is, without exception, painted with opaque paint in presently known cellular phones, whereby the reinforcing wire can be well left on the peripheral portion without in any way interfering with the subsequent use of the product. On the other hand, the reinforcing wire can be left completely visible on the product, even intentionally: a shiny metal wire, a black fibrous wire, or other threaded part embedded in a transparent plastic product can have an unusual and interesting visual effect. The portion of the reinforcing wire that remains inside the finished product may even be shaped in the form of, for example, a letter, an emblem, or other desired symbol during manufacture.

If it is desired to remove the reinforcing wire, it can simply be pulled out of the product, especially if its portion within the product is straight and relatively ly-10 short. However, there is a risk of product breakdown. If the reinforcing wire is metal, it may be heated prior to drawing, for example by induction, in which case it will more easily leave the plastic material. Removal generally does not completely remove the trace left by the reinforcing wire on the transparent product, but leaves the point where the reinforcing wire has been attached.

Figure 10 illustrates one possible way to utilize a reinforcing wire at a point in the manufacturing process where the reinforcing wire passing through the workpiece comes out at some point and forms a thread end 1001 protruding out of the workpiece; for example, a step of detaching the workpiece from the right at the edge of the 20 workpieces, but just a little outside. On the other hand, there may also be phases in which the workpiece is still attached to • the successive workpieces; in the tape, if at least one reinforcing wire is initially placed in the mold so that its end fits snugly or can be cut properly without removing the workpiece from the tape. In Figure 10, workpiece 1002 has just come from a dyeing or lacquering machine, whereby paint or lacquer applied to its surface is still flowing. Yarn v: end 1001 is used as a drain wire, i.e. the workpiece is held in such a position and / or moved so that the dye or varnish drips over and drips off the wire end 1001. Thus, for example, a workpiece can be kept. in place, the thread end 1001 is downwardly rotatable or rotatable such that the thread end 30 1001 is continuously pointed away from the center of rotation of motion. Wire end 1001 prevents paint or lacquer from accumulating on the workpiece edge.

;. Figure 11 illustrates a manufacturing process according to a preferred embodiment of the invention. A strip made of plastic, metal or other sufficiently flexible material, obtained from a roll 35 1101, is used to form the strip of tape. The strip may be pre-patterned. The strip passes through an injection molding mold 1102. Whenever a die is molded into a die, it is attached to the tape either by passing the tape through the injection die or any part thereof, or by simply attaching the tape to the surface of the die die or a portion thereof. In principle, it would be possible to attach injection molded parts to the tape even after injection molding, but this would add 5 more steps to the process.

In the process of Figure 11, the injection molded bodies are immersed in a pool 1103, from which the strip of tape rises at position 1104, for example at an angle of 60 degrees to the horizontal; the angle can be chosen so that excess lacquer flows as far as possible away from the pieces. For example, varnish can be used to improve the scratch resistance of articles 10. To dry the varnish, the strip of material passes through an evaporation unit 1105, whereby the flow of de-dusted air or shielding gas evaporates the solvents in the varnish. At position 1106, the varnish is cured by ultraviolet light, at 1107, pre-lacquered pieces can be patterned by printing or the like, and at 1108, the pieces are cut off from the 15 strips, for example, by heat stamping. The finished pieces leave the process at step 1109 and what is left of the tape can be wound up on reel 1110.

Ultraviolet curing means that acrylate lacquer is used in the process of Figure 11. The advantage of ultraviolet curing is its speed: as early as three seconds of ultraviolet exposure, sufficient curing of the plastic lenses of the mobile phone 20 is achieved. If silicate lacquer was used, ultraviolet curing would have to be replaced by heat treatment in the oven. In the process, this would mean that after the evaporator 1105, the pieces would be cut off from the tape in the same manner as in Fig. 11, 1108, then placed in a separate magazine (cf. diapro projectors:.: Used for slipper) and transferred to the curing oven.

. Figure 12 shows a block of strips generated in the process of Figure 11 as a result of step 1102. The tape 1201 has printing patterns 1202 at regular intervals and the injection molding is applied thereto so that each printing pattern will form a surface pattern of a particular injection molding. The invention as such does not require printing, but the tape can also be used to form only the tape. Alignment or markings 1203 on the tape may be used to assist in the alignment.

For example, guiding and / or driving wheels which are opposed to each other can be used to guide the belt in a manner known per se. The strip may also have grooves or other moldings to control the flow of the varnish while the varnish is still fluid.

112455 10

Figure 13 further illustrates a manufacturing process according to a preferred embodiment of the invention. One or more yarns obtained from the reel 1301 are used to form the workpiece web. In the mold 1302, workpieces are formed by the method of solidifying a liquid or viscous raw material so that each workpiece passes through a particular part. At 1303, the workpieces are lacquered by spraying and the solvents in lacquer 1304 are evaporated. Ultraviolet curing occurs at 1305 and may be followed by other processing steps such as one or more imprints 1306 and 1307, curing of the dye used in the printing by one of the irradiation methods 1308, and separation of Kap-10 beads from conveyor yarn or yarns at 1309. paragraphs 1311 are removed from the process. In order to support and move the strip of tape, various strip conveyors may be used in the process, of which Figure 13 specifically shows a conveyor with a disposable strip 1312, where the purpose of the disposable strip 15 is to protect the actual conveyor from spray lacquer.

Figures 14 and 15 illustrate a workpiece shape that can be produced in step 1302 of the process of Figure 13. The workpiece consists of two circular rectangular utility pieces 1401 and 1402, two conveyor tabs 1403 associated with each utility piece, and a jig 140b to form a workpiece. is illustrated by reference numerals 1405 and 1406. Fig. 15 is a sectional view taken along the dashed line 1407 and shows in particular an exemplary form of the Joits. In Fig. 15, the yoke consists of a pri, a numbered pouring channel 1501, a flow channel 1502, and a secondary pouring channel 1503. Fig. 15 also shows an exemplary conveyor tab! 25 1403 cross-section. It is common for the conveyor tongue and the jute to remove both of them from the utility piece before the utility piece is finally complete. In Figure 15, thread 1406 passes through conveyor tab 1403, but could also engage the surface of conveyor tab.

The invention has been described above in connection with an injection molding process only. A particular advantage of injection molding is that it is a method generally used for making smaller and dimensionally accurate plastic parts and that the flow of the material before it solidifies is quite well controlled so that the invention is easy to apply. However, the invention can also be applied to casting or to chemical or physico-chemical solidification processes in connection with the manufacturing processes.

Claims (8)

A method for treating workpieces (1401-1404) in a manufacturing process comprising forming individual workpieces by solidifying a liquid or viscous material, wherein in method 5, successive workpieces, after solidifying the material, form a web, said web comprising a nonwoven web 140 two longitudinal reinforcements (1405, 1406) of said strip are used and the material to be solidified is introduced at position 10 (1501) between the two reinforcements, characterized in that in the method each workpiece comprises at least two utility pieces (1401, 1402) , so that the point where the material to be solidified is fed is located between the useful bodies. 1 1 9 J R E I I I I ΐ- Li J u Method according to claim 1, characterized in that each workpiece comprises a part to be removed in addition to the utility pieces. of which is a yoke formed by a pouring channel (1404). Method according to claim 2, characterized in that the removable part has conveyor tabs (1403) for attaching the workpiece to the reinforcements. Method according to Claim 3, characterized in that the reinforcement is a wire (1405, 1406) which is connected to the part to be removed and continues with successive workpieces. ': * Between the lids between the parts to be removed. ··. ·. Method according to Claim 3, characterized in that the gain is a '··' band. v Method according to claim 1, characterized in that the workpieces: 25 are formed by injection molding. A method according to claim 1, characterized in that, after solidification of the liquid or viscous material, it comprises at least one of the following working steps: painting and / or varnishing, draining, evaporation, ultraviolet curing, printing; go through that step as a ribbon. An apparatus for treating workpieces in a manufacturing process comprising forming separate workpieces by solidifying a liquid or viscous material, the apparatus comprising means for forming a tape from successive workpieces, means for attaching a reinforcement (1405, 1406) to a material to be stiffened, and at a point (1501) between the longitudinal reinforcements (1405, 1406) of the two said strips, characterized in that it comprises means for forming at least two utility pieces (1401, 1402) in each workpiece such that the point where the solidifying material is fed between.