A baffle or reinforcement includes a carrier and one or more thermally expandable materials designed for positioning in cavities of, for instance, automotive or aerospace beams, pillars, rails, doors, etc. to provide acoustic dampening and/or sealing and/or structural reinforcement. The carrier is generally formed from plastic or metal surrounded with the expandable material. When inserted into the cavity and by the action of the heat applied in the electrophoresis baking oven, the foam material expands to seal the cavity and/or bond the carrier to the member.
Such baffles or reinforcements may be formed using various techniques. These techniques include extruding the foamable material with the carrier, overmolding the foamable material onto the carrier, or assembling separately produced foamable material and carrier using mechanical fasteners or an adhesive. While each of these techniques may produce a suitable baffle or reinforcement, these techniques suffer from various drawbacks, including high tooling cost. Therefore, a new design and tooling concept and related process is needed that reduces tooling cost, yet produces baffles or reinforcements that meet acoustic and/or sealing performance and/or structural support requirements.
Accordingly, one object of the invention is to provide a method that overcomes the drawbacks of the known art. According to the invention, this is achieved by the features of the first claim.
A baffle or reinforcement may be formed from a tool that includes a mold having a first portion for receiving an expandable material and a second portion for receiving the expandable material and a carrier material. In the following, just baffle is named but the same applies to reinforcement. The mold has a first side at least partially spaced from a second side. A plate is disposed between the first side and the second side of the mold. The plate is selectively moveable to move the expandable material from the first portion to the second portion. For example, the plate may be rotated or translated to move the expandable material from the first portion to the second portion. Moreover, the first portion and second portions may be disposed on separate molds of two or more different machines.
A method of forming the baffle includes molding an expandable material in a first cavity of a mold, the mold having a first side and a second side partially defining the first cavity, and a plate disposed therebetween, rotating the plate to move the expandable material to a second cavity defined by the mold, and overmolding a carrier material onto the expandable material in a second cavity of the mold partially defined by the first side and the second side.
As illustrated in
The first side 110 and second side 115 of the mold 105 may each include a first portion 120 and a second portion 125. The first portion 120 may define a first cavity 130 that receives the heated expandable material. The first cavity 130 defines a shape of the expandable material after being injected into the mold 105. The second portion 125 may define a second cavity 135 that receives the cooled expandable material and the heated carrier material. The second cavity 135 defines the shape of an assembled baffle or reinforcement (e.g., having the cooled expandable material and carrier material).
A plate 140 may be disposed between the first side 110 and the second side 115 of the mold 105, and partially define the first cavity 130 and the second cavity 135. When injecting the expandable material and/or carrier material into the mold 105, the first side 110 and second side 115 of the mold 105 may be pressed upon opposite surfaces of the plate 140. Specifically, the first side 110 may press upon a back surface 145, while the second side 115 may press upon a front surface 150. When separated, however, the plate 140 may stay disposed on either the first side 110 or the second side 115. As illustrated in
The plate 140 is selectively moveable to, for example, move the expandable material from a first position to a second position. In the first position, the expandable material is disposed in the first cavity 130 in the first portion 120 of the mold 105. In the second position, however, the expandable material is disposed in the second cavity 135 in the second portion 125 of the mold 105. Specifically, the expandable material may be injected into the first cavity 130 while the mold 105 is closed. When the expandable material has at least partially cooled, the first side 110 and second side 115 of the mold 105 may be separated. The plate 140 may then rotate about a rotation axis R until the cooled expandable material is disposed within the second cavity 135.
The plate 140 may include a knob 155 integrally formed with and extending from the plate 140 for selectively rotating the plate 140 from the first position to the second position. The knob 155 may be located on the plate 140 between the first portion 120 and the second portion 125 and define the rotation axis R about which the plate 140 rotates. Alternatively, the knob 155 may be located elsewhere on the plate 140. For example, the knob 155 may be located in a corner of the plate 140 while the rotation axis R is near the center of the plate 140.
A tool operator may manually rotate the plate 140 by turning the knob 155. Alternatively, the plate 140 may be rotated by a motor (not shown). The motor may be disposed on the first side 110 or second side 115 of the mold 105. Moreover, the motor may allow the plate 140 to rotate while the first side 110 and second side 115 of the mold 105 are closed.
In one exemplary approach, the plate 140 may be configured for translation movement to move the expandable material from the first cavity 130 to the second cavity 135. For example, the plate 140 may be configured to slide the expandable material toward the second cavity 135.
While moving from the first position to the second position, the mold 105 may be opened or closed. For purposes of clarity, however, the first side 110 and second side 115 are separated in
Returning to
The expandable material may be formed from various materials. For example, the expandable material may include an acoustic foam that attenuates sound waves by increasing air resistance. The acoustic foam may expand when heated to a minimum temperature. Therefore, when the carrier material is injected into the second cavity 135, the temperature of the carrier material when injected may be higher than that minimum temperature, which may cause the expandable material to react on the surface and generate a chemical bonding of the carrier material with the expandable material. As the carrier material and expandable material cool, the expandable material may keep its expandable behavior so that it may be expanded after the baffle or reinforcement is placed in a cavity. Alternatively, or in addition, the expandable material may include a structural foam.
Further, the superficial melt reaction of the expandable material 180 in contact with the hot carrier material 175 in the overmolding process may generate an additional chemical bonding that may be used to secure the carrier 175 to the expandable material. For example, in the overmolding process, the expandable material 180 may be injected at a temperature (e.g., 80° C. to 110° C.), which is below the temperature that starts the expansion of the expandable material 180 (e.g., 120° C.-145° C.). The expandable material 180 may cool, and the carrier material may be injected over the expandable material 180 at a temperature between, for example, 180° C. and 260° C. The carrier material may then cool to a temperature below the temperature at which the expandable material 180 expands (e.g., 120° C.-145° C.). With this process, the carrier material adheres to the expandable material 180. The contact surface of the expandable material is exposed to an elevated temperature, above the melting and foaming temperature, causing a superficial foaming and chemical bonding between the expandable material 180 and the carrier material. This adhesion allows the expandable material 180 to adhere to the carrier 175 without mechanical fittings.
When the exemplary baffle 170 of
The carrier 175 may further define holes 195 over portions “sandwiching” of the carrier 175 that “sandwich” the expandable material 180 and/or another expandable or non-expandable material 190. The holes 195 may have various diameters, depending on the application. For example, the diameter of the holes 195 may be 2-20 mm, and preferably, 5-12 mm. The holes 195 may be used to assist in the process of overmolding the carrier 175 onto the expandable material 180. For example, the holes 195 may be used to support the expandable material 180 and 190 in the tool 100 while the carrier 175 is being formed. Also, the holes 195 may allow one or more of the expandable materials 180 and 190 to escape the carrier 175 and create a noise absorption surface for improved acoustic performance.
The baffle 170 of
Further, for the exemplary baffles 170 illustrated in
Referring to
Although shown separately, various combinations of the features illustrated in
Block 305 may include joining the first side 110 of the mold 105 to the second side 115 of the mold 105. As previously discussed, the plate 140 may be disposed between the first side 110 and the second side 115. The plate 140 may further be disposed on either the first side 110 or second side 115 of the mold 105 when the first side 110 is separated from the second side 115.
Block 310 may include injecting the expandable material 180 into the first cavity 130 of the mold 105. The first cavity 130 is located in the first portion 120 of the mold 105. The expandable material 180 may be heated and injected into the first cavity 130 in a fluid state. The first cavity 130 may define various cross-sections for the expandable material 180, as previously discussed. Additionally, as previously discussed, block 310 may further include injecting another expandable material 190.
Decision point 315 may include determining whether the expandable material 180 has cooled to a solid state. This determination may be based upon a predetermined amount of time, or using a temperature sensor within the mold 105. If the expandable material 180 is still in a fluid state, the process 300 continues to wait. If the expandable material 180 has cooled, the process 300 continues with block 320.
Block 320 may include separating the first and second sides 110 and 115 of the mold 105 after the expandable material 180 has had time to cool. Again, the plate 140 may stay disposed on either the first side 110 or the second side 115 when the first side 110 and second side 115 are separated.
Block 325 may include moving the plate 140 to move the expandable material 180 from the first cavity 130 to the second cavity 135. As previously discussed, the plate 140 may be rotated or translated automatically using a motor or manually by an operator. If moved automatically by the motor, the first side 110 and second side 115 of the mold 105 need not necessarily be separated. As previously discussed, the fixation element 165 may be inserted at the same time, just before, or just after the expandable material 180 is moved from the first cavity 130 to the second cavity 135.
Block 330 may include joining the first and second sides 110 and 115 of the mold 105 with the plate 140 disposed therebetween. When joined, the first side 110 and second side 115 of the mold 105 need not actually touch. For instance, the plate 140 or another element may prevent the first side 110 and second side 115 of the mold 105 from actually touching.
Block 335 may include injecting the carrier material into the mold 105. The carrier material may be heated to a fluid state and injected into the mold 105 while in the fluid state. The carrier material may at least partially fill the second cavity 135 and be at least partially injected about the expandable material 180. As previously discussed, the heat of the carrier material 175 will generate a superficial melt of the expandable material 180 that will assist in the connection of the various materials. The cooling of the tool will be optimized to quickly evacuate the amount of heat, such that no reaction will occur in the core of the expandable material 180.
Decision point 340 may include determining whether the carrier material and expandable material 180 have cooled. As with decision point 315, this determination may be based upon a predetermined amount of time or using a temperature sensor within the mold 105. If the carrier material is still in a fluid state, the process 300 continues to wait. If the carrier material has cooled, the process 300 continues with block 345.
Block 345 may include ejecting the baffle 170 after the carrier material and expandable material 180 have cooled. Ejecting the baffle 170 may include separating the first side 110 and the second side 115 of the mold 105, and removing the baffle 170 from the second cavity 135.
In one exemplary implementation, the tool 100 may simultaneously inject expandable or carrier material for two different baffles 170. For instance, the tool 100 may inject the expandable material 180 into the first cavity 130 to begin forming one baffle 170 while overmolding the carrier material onto the expandable material 180 into the second cavity 135 to finish forming another baffle 170. Then, the baffle 170 in the second cavity 135 is ejected from the tool 100 and the expandable material 180 in the first cavity 130 may be moved to the second cavity 135. While the expandable material 180 is in the second cavity 135, the carrier material is injected to finish that baffle 170 and the expandable material 180 for a new baffle 170 may be injected into the first cavity 130. This cycle may continue so that the tool 100 is constantly producing parts of two different baffles 170.
With regard to the processes, systems, methods, heuristics, etc. described herein, it should be understood that, although the steps of such processes, etc. have been described as occurring according to a certain ordered sequence, such processes could be practiced with the described steps performed in an order other than the order described herein. It further should be understood that certain steps could be performed simultaneously, that other steps could be added, or that certain steps described herein could be omitted. In other words, the descriptions of processes herein are provided for the purpose of illustrating certain embodiments, and should in no way be construed so as to limit the claimed invention.
Accordingly, it is to be understood that the above description is intended to be illustrative and not restrictive. Many embodiments and applications other than the examples provided would be apparent upon reading the above description. The scope of the invention should be determined, not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. It is anticipated and intended that future developments will occur in the technologies discussed herein, and that the disclosed systems and methods will be incorporated into such future embodiments. In sum, it should be understood that the invention is capable of modification and variation.
All terms used in the claims are intended to be given their broadest reasonable constructions and their ordinary meanings as understood by those knowledgeable in the technologies described herein unless an explicit indication to the contrary in made herein. In particular, use of the singular articles such as “a,” “the,” “said,” etc. should be read to recite one or more of the indicated elements unless a claim recites an explicit limitation to the contrary.
Number | Date | Country | Kind |
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09177996.7 | Dec 2009 | EP | regional |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP10/68866 | 12/3/2010 | WO | 00 | 8/13/2012 |