Abstract:
An in-mold decorating and laser etching method prints a plurality of layers on a flat thin sheet plastic substrate, including combinations of opaque and colored, including translucent and smoked, forms the substrate into a contoured three dimensional workpiece, injection molds the workpiece to an injection molded part, and laser etches a designated graphic in the opaque layer on the part.

Description:
BACKGROUND AND SUMMARY 
     The invention relates to in-mold decorating, and more particularly to in-mold decorating with laser etching. 
     In-mold decorating is known in the art. A flat thin plastic substrate, such as polycarbonate, polyester, etc. is provided in extruded sheet form, typically 0.005 to 0.030 inch thick. One or more ink layers are then printed on the substrate, which ink layers may be printed to provide desired graphics. The flat substrate is then formed into a contoured three-dimensional workpiece, which forming may be aided by heat, i.e. thermal-forming, or without heat, i.e. cold forming. The substrate may then be cut into a plurality of subpieces, for example each containing one or two contoured items. The substrate, or each subpiece if so cut, is then placed in an injection mold, followed by closing of the mold, then injection of molten plastic against the workpiece to fuse therewith and form an injection molded part, following by opening of the mold, and removal of the part from the injection mold. Laser etching is also known in the art. The laser is used to ablate designated portions of ink layers to provide a desired graphic. 
     The present invention provides an in-mold decorating and laser etching method combining the best aspects of in-mold decorating and of laser etching and affording both lower manufacturing cost and higher image quality. In a further desirable aspect, the invention enables numerous applications and functional features, including both daytime and nighttime display of the same graphic on the same item, different color displays for nighttime and daytime of the same graphic on the same item, separate displays for nighttime and daytime on the same item, different color and multicolor dual displays for nighttime and/or daytime on the same item, semi-transparent or blank displays and selective color displays of the same graphic on the same item, and numerous manufacturing sequencing options for cost effectiveness. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded perspective view of a layering sequence for in-mold decorating and laser etching in accordance with the invention. 
     FIG. 2 is an assembled perspective view of the layered substrate of FIG.  1 . 
     FIG. 3 is a sectional view taken along line  3 — 3  of FIG.  2 . 
     FIG. 4 is a perspective view showing the substrate of FIG. 3 after forming into a contoured three dimensional workpiece. 
     FIG. 5 is a perspective view of the workpiece of FIG. 4 after a cutting step. 
     FIG. 6 is a schematic sectional view illustrating injection molding. 
     FIG. 7 is a sectional view taken along line  7 — 7  of FIG.  6 . 
     FIG. 8 is a view similar to FIG. 7, and illustrates an alternate embodiment. 
     FIG. 9 is a perspective view illustrating the injection molded part after the injection molding of FIGS. 6 and 7. 
     FIG. 10 is a perspective view from below of the part of FIG.  9 . 
     FIG. 11 is a sectional view taken along line  11 — 11  of FIG. 10, and illustrates laser etching. 
     FIG. 12 is a top view of the part of FIG. 11 after laser etching. 
     FIG. 13 is a sectional view taken along line  13 — 13  of FIG.  12 . 
     FIG. 14 is an enlarged view taken along line  14 — 14  of FIG.  12 . FIG. 14 illustrates daytime viewing. 
     FIG. 15 is a side view partially in section illustrating an application of the part of FIGS. 12 and 13. 
     FIG. 16 is like FIG.  15  and shows another mode of operation. 
     FIG. 17 is like FIG.  15  and shows a further mode of operation. 
     FIG. 18 is like FIG.  14  and illustrates nighttime viewing. 
     FIG. 19 is like FIG.  1  and shows another embodiment. 
     FIG. 20 is like FIG.  14  and illustrates daytime viewing for the combination of FIG.  19 . 
     FIG. 21 is like FIG.  20  and illustrates nighttime viewing. 
     FIG. 22 is like FIG.  1  and shows a further embodiment. 
     FIG. 23 is like FIG.  14  and illustrates daytime viewing for the combination of FIG.  22 . 
     FIG. 24 is like FIG.  23  and illustrates nighttime viewing. 
     FIG. 25 is like FIG.  1  and shows a further embodiment. 
     FIG. 26 is like a portion of FIG.  13  and illustrates the formed part for the combination of FIG.  25 . 
     FIG. 27 is like FIG.  14  and illustrates daytime viewing for the combination of FIG.  25 . 
     FIG. 28 is like FIG.  27  and illustrates nighttime viewing. 
     FIG. 29 is like FIG.  1  and shows a further embodiment. 
     FIG. 30 is similar to a portion of FIG.  9  and illustrates the formed part for the combination of FIG.  29 . 
     FIG. 31 is like FIG.  1  and shows a further embodiment. 
     FIG. 32 is like FIG.  3  and shows the substrate layering for the combination of FIG.  31 . 
     FIG. 33 is like FIG.  12  and illustrates a top daytime view of the part formed by the combination of FIG.  31 . 
     FIG. 34 is a sectional view taken along line  34 — 34  of FIG.  33 . 
     FIG. 35 is like FIG.  33  and illustrates a top nighttime view. 
     FIG. 36 is a sectional view taken along line  36 — 36  of FIG.  35 . 
     FIG. 37 is like FIG.  2  and shows a further embodiment. 
     FIG. 38 is like FIG.  4  and shows the contoured workpiece for the combination of FIG.  37 . 
     FIG. 39 is a perspective view of the structure of FIG. 38 after cutting into a plurality of subworkpieces. 
     FIG. 40 is like FIG.  9  and illustrates the formed part from the construction of FIG.  39 . 
     FIG. 41 is like FIG.  12  and illustrates the part of FIG. 40 after laser etching. 
     FIG. 42 is a perspective view of the part of FIG.  41 . 
     FIG. 43 is a rear elevational view of the part of FIG.  41 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 shows a flat thin sheet plastic substrate  50 , for example polycarbonate, polyester, etc., extruded in sheet form, and typically 0.005 to 0.030 inch thick. A translucent white layer  52  is printed on substrate  50 . Layer  52  is preferably screen printed on substrate  50 , though other methods may be used for applying such layer, and other layers, to be described, including offset printing, roll coating, and other methods of applying or coating a layer. Layer  52  is preferably printed with a translucent white catalyzed ink to achieve a high melt temperature and abrasion resistance. Following printing of layer  52 , opaque layers  54  and  56  and hard coat layer  58  are printed on the substrate, to provide the layered structure shown in FIGS. 2 and 3. Each of opaque layers  54  and  56  is a black screen printing ink. A single opaque layer may be sufficient, though two layers are preferred, to minimize pinhole leakage, and maximize opacity. Hard coat layer  58  is transparent and preferably has a high abrasion resistance. Layer  52  is printed with laser-vaporization-resistant ink. Layer  54 ,  56 ,  58  are printed with laser-vaporization-susceptible inks. In FIGS. 2 and 3, layers  52 ,  54 ,  56 ,  58  are collectively designated by reference character  60 . 
     Layered flat substrate  50 , FIG. 2, with layering  60  thereon, is formed into a contoured three dimensional workpiece  62 , FIG.  4 . The forming is preferably aided by heat in accordance with known thermal-forming techniques, and preferably also aided by vacuum and/or pressure in accordance with known thermo-vacuum forming techniques. Alternatively, the substrate may be cold formed into a contoured three dimensional workpiece. The layered and formed substrate is then cut, e.g. in accordance with known die-cutting techniques, to trim and remove the portion of the substrate which will not be used in the final part, to yield the workpiece  62  shown in FIG.  5 . The workpiece is then placed in an injection mold  64 , FIG. 6, followed by injecting of molten plastic against the workpiece to fuse therewith and form an injection molded part, followed by removal of the part from the injection mold. 
     Injection molding is known, and will be only briefly described. The mold has a female mold half  66  and a male mold half  68  defining a mold cavity  70  therebetween receiving workpiece  62 . The mold is initially open, with mold halves  66  and  68  separated. Workpiece  62  is placed in female mold half  66 , whereafter one or both of the mold halves are moved towards each other to close the mold. FIGS. 6 and 7 show the mold in its closed condition. Plastic resin, preferably polycarbonate, pellets  72  are introduced at hopper  74  into cooling zone  76  of heating cylinder or barrel  78 . An actuator  80  has an extendable and retractable plunger or ram or piston  82  pushing the pellets into injection chamber  84  in heating zone  86 , wherein the pellets are melted to molten plastic and spread by torpedo or spreader  88  and injected through nozzle  90  and sprue or runner  92  into cavity  70 , all as is known. The injected molten plastic in cavity  70  fuses with workpiece  62  to form an injection molded part. After cooling, the mold is opened, and the part removed from the mold. FIG. 8 shows an alternate embodiment, wherein one of the mold halves, such as female mold half  66 , includes knife edge projections such as  94  cutting the contoured substrate of FIG. 4 during the mold closing step, to eliminate the die-cutting step between FIGS. 4 and 5. 
     FIGS. 9 and 10 show the molded part  96  removed from the mold. The molded part includes substrate  50 , printed layers  60 , and fused and hardened plastic base  98 , FIGS. 11 and 13, which had filled mold cavity  70 . In the embodiment shown, male mold half  68  includes blocking surfaces  100 ,  102 , FIG. 7, engaging substrate  50  at respective designated windows,  104 ,  106 , FIGS. 10,  13 , in alignment with white translucent layer  52  and blocking impingement of molten plastic against substrate  50  at such respective window. Molded part  96  is then etched with laser  108 , FIG. 11, at laser beam  109  to provide a designated graphic in the opaque layers on the part, for example “UP” at  110  and “DN” at  112 , FIG.  12 . Various types of lasers are commercially available for such etching applications, for example one of which is “Insta Mark Laser Marking Systems”, Insignia Icon Stylus, Control Laser Corporation, 7503 Chancellor Drive, Orlando, Fla., USA 32809. As noted above, hard coat layer  58  and opaque layers  56  and  54  are printed with laser-vaporization-susceptible ink, whereby such layers ablate away as etched along the desired graphic by laser  108 . White translucent layer  52  is printed with laser-vaporization-resistant ink and hence does not ablate away. 
     FIG. 14 illustrates the daytime visual display of molded part  96 . Incoming ambient light at  114  is reflected by layer  52  back towards the user or viewer at  116 . Thus, layer  52  provides a daytime color showing the designated graphics “UP” and “DN” as white lettering against the black background of opaque layers  54 ,  52  through transparent outer hard coat layer  58 . 
     FIG. 18 illustrates the nighttime visual display in conjunction with the application illustrated in FIGS. 15-17. Molded part  96  is in the form of a toggle or paddle button nested in an automotive instrument cluster panel  118 , FIG. 15, and having a central molded stem  120  engaging switch  122  for actuating the latter between a first position, FIG. 16, illuminating light bulb  124 , and a second position, FIG. 17, illuminating light bulb  126 . Part  96  rocks about integrally molded trinions  128 ,  130 . In the central neutral position shown in FIG. 15, neither light bulb  124  nor  126  is illuminated, and daytime viewing is as shown in FIG. 14, with both “UP” and “DN” being visible by reflection of ambient light as white lettering against a black background. In the nighttime operational mode illustrated in FIG. 16, “UP” on leftward rocking of molded part rocker button  96  as shown at arrow  132 , light bulb  124  is illuminated, and light therefrom passes through substrate  50  and white translucent layer  52  as shown at arrow  134 , FIG. 18, providing an illuminated white “UP” graphic at  110 . Likewise, when rocker button molded part  96  is rocked rightwardly as shown at arrow  136  in FIG. 17, light from illuminated bulb  126  shines through substrate  50  and layer  52 , providing an illuminated white “DN” graphic at  112 . In each of the rocked positions of FIGS. 16 and 17, the light passing through layer  52  at  134  in addition to the reflective ambient light at  116 , FIG. 14, provides additional and brighter indication of the condition of the switch, including during daytime. This provides feedback to the user or driver of whether the switch is in its up or down actuated position. For example, during daytime, in the position of FIG. 16, the graphic “UP” at  110  will be brighter than the graphic “DN” at  112 , and hence the user will know the switch is in its activated “UP” condition for the controlled function, e.g. power window activated “UP”. At nighttime, in the position of FIG. 16, the “UP” graphic at  110  will be visible due to the through-transmitted light at  134 , and the “DN” graphic at  112  will not be visible, and hence the noted feedback will be provided to the user. 
     In another embodiment, both light bulbs  124  and  126  are always illuminated at nighttime, e.g. when the driver turns on his parking lights or headlights. In this embodiment, both the “UP” graphic at  110  and the “DN” graphic at  112  are visible to the driver, including at nighttime due to transmitted light  134 . The driver may thus select which function is desired, e.g. window “UP” or window down. Other combinations are possible. 
     Substrate  50  has first and second oppositely facing surfaces  140  and  142 , FIG.  1 . First surface  140  faces the user. In backlit applications, e.g. FIGS. 15-18, second surface  142  faces the backlight,  124 ,  126 . These definitions of first and second surfaces are commonly used in the printing art, for example first surface printing, second surface printing, and so on. In the embodiments described thus far, the noted layers are printed on the first surface, and the molten plastic from runner sprue  92  is injected against the second surface. The laser etching step is performed by directing the laser beam  109  at the first surface. In an alternate embodiment, color layer  52  is printed on second surface  142 , i.e. on the opposite side of the substrate from the opaque layers  54 ,  56 , to be described. 
     FIG. 19 shows a further embodiment with first and second color layers  52  and  144  printed on substrate  50 . Layer  52  is a translucent daytime color ink, preferably white as noted above. Layer  144  is printed with a nighttime color ink, for example amber, or other colors as desired. In daytime, FIG. 20, the part displays to the user the daytime color at the graphic, as shown by reflected ambient light  114 ,  116 . At nighttime with a backlight, the part displays to the user the nighttime color at the graphic, for example ambient as shown at  134  in FIG.  21 . In FIG. 19, color layers  52  and  144  are printed on opposite sides of the substrate. 
     In an alternate embodiment as shown in FIGS. 22-24, layers  144  and  52  are printed on the same side of the substrate, which may be the first surface as shown, or alternatively may be the second surface. The daytime color at the graphic is white as shown in FIG. 23 at reflected ambient light  114 ,  116 . The nighttime color at the graphic is amber as shown in FIG. 24 at  134  from the backlight. 
     FIG. 25 shows an embodiment similar to FIG. 19, except that color layer  144  has been replaced with two layers  146  and  148  of different color, one for each window  104  and  106 , FIGS. 26 and 13. Each window has a daytime reflective color as illustrated in FIG.  27 . Window  104  has a nighttime color provided by layer  146 , like that illustrated in FIG.  21 . Window  106  has a different nighttime color provided by layer  148 , FIG.  28 . 
     FIGS. 29 and 30 show a further embodiment reducing the amount of ink used, for cost savings. Layer  144  of FIG. 19 is reduced in size as shown at layer  150  in FIG. 29 to cover only the top of the molded part, which is the portion where the graphic is. Layer  52  may also be reduced in size. 
     FIGS. 31-36 show a further embodiment. FIG. 31 includes substrate  50  having the following layers printed thereon: opaque layer  152 ; amber layer  154 ; translucent white layer  156 ; smoked translucent ink layer  158 ; opaque layer  160 ; transparent hardcoat layer  58 . Layers  152 ,  154 ,  158  are in alignment with window  104 . Layers  156 ,  160  are in alignment with window  106 . The molded part is laser etched to provide the graphics shown in FIG. 35 at the resistive heater symbol at  162 , and the text graphic “MIRR HEAT” at  164 , for example, for a rocker or paddle switch controlling an electrically heated side mirror on an automobile. In daytime, smoked translucent layer  158  reflects ambient light as shown at  166 ,  168 , FIG. 34, and blocks user view of graphics thereunder. The respective half of the rocker button part aligned with window  104  thus appears blank as shown in FIG. 33 at rocker button portion  170 , i.e. graphic  162  is not visible. Also in daytime, white translucent layer  156  reflects ambient light as shown at  172 ,  174 , FIG. 34, such that the user sees the etched graphic “MIRR HEAT” at  164  aligned with window  106 . This is shown in FIG. 33 at rocker button half  176  where the user sees graphic  164  “MIRR HEAT” during daytime, which graphic is white because layer  156  is the color white. Other colors may be chosen. At nighttime, with illuminated backlights, the resistive heater symbol graphic on rocker button half  170  is visible as shown in FIG. 35 at  162 . The graphic color is amber due to the transmitted light as shown at  178  passing through amber layer  154  from the backlight. The other graphic “MIRR HEAT” at  164  at rocker button half  176  is also visible due to light at  180 , FIG. 36, passing through white layer  156  from the backlight. 
     FIG. 37 is similar to FIG.  2  and shows a further embodiment with a plurality of sets of layers  60  printed on substrate  50 . The substrate is formed, FIG. 38 into a three dimensional substrate, similarly to FIG.  4 . The substrate is cut, preferably by die cutting, into a plurality of workpieces, one of which is shown at  190  in FIG.  39 . Each of the workpieces is placed in an injection mold and molded as above described. Each workpiece  190  has at least one product portion, for example product portions  192 ,  194 , to be formed into the respective part, and a registration portion  196  at the periphery of the product portion and which may link a pair of product portions as shown. Workpiece  190  with both product portions  192  and  194  and registration periphery portion  196  is placed in the mold, with registration portion  196  in registration with the mold. A second cutting step is performed, preferably by knife edges such as  94 , FIG. 8, in the mold and during the mold closing step to further cut the substrate prior to the injecting step, FIG.  6 . The noted second cutting step at least partially detaches registration portion  196  from product portions  192 ,  194 . During the forming step from the construction of FIG. 37 to the construction of FIG. 38, registration marks such as  198  and  200  are formed in registration portion  196 . The registration marks are three dimensional deformations of substrate  50  at registration portion  196 . Further registration marks such as  202  and  204  are formed during the first mentioned cutting step between the constructions of FIGS. 38 and 39. Registration marks  202 ,  204  are openings cut through substrate  50  at registration portion  196  during the noted first cutting step. After the noted second cutting step during closing of the mold, and the molding operation, the mold is opened, and each part removed, to provide the molded parts as above described, and as shown at  206 , FIG.  40 . Designated graphics such as  208 ,  210 , FIG. 41, are then laser etched in the opaque layers  52 ,  54  on the part at respective windows  212 ,  214 , FIG. 43, formed by blocking surfaces  100 ,  102  in the mold, as above described. 
     It is recognized that various equivalents, alternatives and modifications are possible within the scope of the appended claims.