Patent Application
20060233956
The present invention generally relates to the manufacture of items. More particularly, the present invention pertains to a device and system for manufacturing items in a single piece workflow and a method of use.
The manufacture of items generally involves a multitude of steps or processes to take the item or part from raw materials to finished part. The particular processes vary from one industry to the next and according to the materials used. However, there are some processes that cut across multiple industries. For example, forming, preparation, and finishing processes are typically utilized in the manufacture of plastic and metal items. In addition, each process typically entails more than one step. More specifically, finishing includes processes such as cleaning, de-greasing, etching, deoxidizing, reducing, painting, chemical deposition, and/or the like. These processes are similar in that they generally involve immersing or otherwise coating a fabricated part in a solution or chemically reactive solution. Typically, a large batch of parts is dipped into a tank, held in the tank for some length of time and then moved to a rinse tank or another tank of some other chemically reactive solution.
A disadvantage associated with conventional metal part fabrication is that parts are processed in a “batch and queue” manner. That is, some steps involve machines that lend themselves to single item workflow, while other steps require batch processing. Thus, parts queue up as they are processed one or a few at a time when the following steps are preformed in great batches. For example, conventional chemical processing and painting systems are generally designed for batching hundreds or thousands of parts through the process. In addition, chemical processing tanks are typically located in a separate facility away from the fabrication process. The tanks are typically large, e.g. a 20,000 gallon capacity, and do not lend themselves to producing a flow of single work pieces. These and other factors lead to large investments of time and materials prior to the production of a first part. Lead time between batches is also quite large and, if a faulty batch is produced or production is stopped while a batch is in process, a great amount of materials will be wasted.
Accordingly, it is desirable to provide a device and system for manufacturing items and a method of use that is capable of overcoming the disadvantages described herein at least to some extent.
The foregoing needs are met, to a great extent, by the present invention, wherein in some embodiments a device and system for finishing items and a method of use is provided.
An embodiment of the present invention relates to a system for coating a plurality of items. The system includes a tank unit to prepare the plurality of items for painting, a painting unit to paint the plurality of items, a drying unit to dry the plurality, and an item conveyer to convey the plurality of items through the system as a flow of single items.
Another embodiment of the present invention pertains to an apparatus for coating a plurality of items. The apparatus includes a tank unit to prepare the plurality of items for painting, a painting unit to paint the plurality of items, a drying unit to dry the plurality, and an item conveyer to convey the plurality of items through the system as a flow of single items.
Yet another embodiment of the present invention relates to a method of coating a plurality of items. In this method, the plurality of items is chemically prepared for painting, the plurality of items are painted and dried, and the plurality of items are conveyed through the system as a flow of single items.
There has thus been outlined, rather broadly, certain embodiments of the invention in order that the detailed description thereof herein may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional embodiments of the invention that will be described below and which will form the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of embodiments in addition to those described and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
The present invention provides, in some embodiments, an item manufacturing system and a method of manufacturing items. In an embodiment, the invention provides an item manufacturing system for manufacturing various items or parts. Advantages of certain embodiments of the item manufacturing system include one or more of: processing a flow of single items; portability; flexibility, use with existing power supply; and the like. As a result of these advantages, the item manufacturing system may generate a finished item from raw materials in a relative compact space and in a relatively short amount of time as compared to conventional manufacturing systems.
In addition, the item manufacturing system is readily adaptable to changes in processing procedures. In this regard, manufactured items or parts are often chemically processed to improve certain characteristics of the item. Examples of characteristics improved by chemical processing include: wear resistance; resistance to corrosion; surface hardness; coating adhesion; and the like. Depending upon the particular processing being performed, the item is subjected to one or more chemical solutions for a predetermined amount of time and at a predetermined temperature. Due to the flexibility and portability of subunits that make up the item manufacturing system, the item manufacturing system may be reconfigured with comparative ease. For example, if, during production, an additional chemical treatment of the item becomes necessary, an additional chemical processing subunit of the item manufacturing system may be integrated. In a conventional system, such a change may require comparatively major re-design and re-tooling.
In addition, chemical processing may be utilized to prepare an item for painting or other finishing steps. An example of a suitable chemical processing of aluminum items includes Alodine 600 conversion coating. Alodine is an oxide layer on the surface of an aluminum item where the oxide crystals form an organized structure of tightly packed hexagonal columns. This provides a surface to which BMS 10-11 zinc chromate primer can readily adhere. Several steps are taken to prepare the aluminum surface for the application of Alodine. These steps optionally include a degreasing operation, alkaline cleaning, and nitric acid etch to remove the oxide layer which naturally forms on aluminum in air. A rinse is typically performed after each cleaning and etching process. The result is a clean, and substantially oxide-free part ready for Alodine. After Alodine is applied, the item is rinsed and dried.
The invention will now be described with reference to the drawing figures, in which like reference numerals refer to like parts throughout. As shown in
In various embodiments, the tank line 12 cleans, degreases, chemically and/or electrochemically etches and/or coats the items 20 as appropriate. In a particular embodiment, the tank line 12 includes a plurality of tanks 12A-12F. The bottoms of one or more of the tanks 12A-12F are slanted to aid in draining. Each of the tanks 12A-12F is configured to contain a solution such as, for example, cleaning solution, acid, Alodine, rinse solution, and the like. Moving the items 20 through the tank line 12 cleans the items 20 using a heated alkaline clean solution, then a first and second water rinse, then a deox solution of nitric and chromic acid, another first and second rinse, then Alodine conversion coating, and a warm rinse, then a warm air dry. The items 20 are then transferred, each in its turn, to the painting unit 14 where they are painted or otherwise coated. In a particular example. The items 20 are dipped twice in a specially controlled paint solution and the solvent is allowed to flash-off for several minutes. The items 20 are conveyed to a paint curing oven 16 to cure the coating to the item 20.
In general, one of the items 20 enters the item finishing system 10 and a finished one of the items 20 leaves the item finishing system 10 each predetermined increment of time. The predetermined increment of time includes any suitable time increments such as, for example 10 seconds, 1 minute, 5 minutes, 15 minutes, and the like. Time increments may be based upon path length of the finishing system 10, duration of individual processes, manufacturer's specifications, empirical data, and the like. In a particular example, the time increment is one minute. That is, one item 20 enters the system and one finished item 20 leaves the system every 60 seconds. Each item 20 is hung from an item carrier 22 and moved through the item finishing system 10 via the item conveyer system 18.
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When the lift cylinder 72 is retracted, the item carriers 22 rest upon the step rail 76. More particularly, one or more tabs 80 on the item carrier 22 engage respective notches 82 in the step rail 76. The step rail 76 is stationary and is attached to the deck assembly 66. Optionally, the tabs 80 include pins 84 directed downward from the tabs 80 and configured to engage respective bores 86 disposed within the transfer rail assembly 62. When the lift cylinder 72 is extended, the pins 84 go into the bores 86 and thereby positively located the item carriers 22 upon the transfer rail assembly 62. This provides a predictable location of the item carriers 22 and less potential for the item carriers 22 to slide or tip. The various components of the walking beam device 24 are constructed from any suitable relatively strong, corrosion resistant, and dimensionally stable material. Suitable materials include 304 and/or 316 stainless steel. Suitable materials for any rolling elements also include SAE 660 bronze.
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Optionally, one or more of the tanks 12A-12F include a weir 100 (shown in
In an embodiment, the item finishing system 10 includes a variable timing feature. For example, as the Alodine solution ages, soaking times are increased. The item finishing system 10 is configured to accommodate this increase in the soak times by included an independent tank transfer device 26 over the Alodine tank 12E. When the solution is new, the tank transfer device 26 is configured to remove the item carrier 22 relatively quickly as compared to when the solution ages.
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In addition, the tank line 12 optionally includes a rinse fluid supply 110 to supply rinse fluid at a controlled rate. In some ,embodiments, one or more of the tanks 12A-12F are configured to rinse solutions from the items 20. If present, the rinse fluid supply 110 adds rinse fluid to the tanks 12B, 12D, and 12F and any excess flows over the edge of the tank, through an opening or through a stand pipe welded through the tank bottom to the collection basin 102 below. The rinse tanks 12B, 12D, and 12F with a first and second rinse have the rinse fluid supplied to the second rinse portion; this fluid drains over the weir 100 separating the two portions; rinse fluid subsequently drains to the collection basin 12. That is, the items 20 are moved through the tanks 12B, 12D, and 12F in a direction opposite to the rinse fluid flow. The rinsed items 20 are removed from the portion of the tank 12B, 12D, and 12F containing the cleanest rinse fluid, thereby maximizing the cleaning efficiency. In an embodiment, the rinse fluid supply 110 is a separate supply tank. In another embodiment, the rinse fluid is supplied from a supply line. Utilizing a separate supply tank includes the advantage of minimizing instances of unrestricted overflow. For example, a 30-gallon polyethylene rinse water storage tank with one or more adjustable flow rate metering pumps provides controlled flow rates and limits spills to about 30 gallons or less.
In an embodiment, the items 20 are dried following chemical processing and prior to being painted. In this embodiment, the tank line 12 includes a dryer 116 that directs a heated air flow towards the items 20. The dryer 116 includes a heater 118 and a blower 120 to induce a flow of heated air and a plurality of louvers 122 to direct this flow of heated air. To further reduce drying time, the rinse tank 12F is optionally heated.
To reduce fumes in the vicinity of the tank line 12, the tank line 12 optionally includes an enclosure 130 and ventilation system 132. The enclosure 130, if present is constructed of a planar and essentially gas impermeable material. In a particular example, the enclosure 130 includes Lexan® panels and doors that are detachably secured about the tank line 12 and provide access to and from the tank line 12. The ventilation system 132 draws air and fumes from the enclosure 130. In a particular example, the ventilation system draws air and fumes downward from between and around the tanks 12A-12F. Supply air is provided by an item entrance and item exit openings in the and/or from slit openings along the top of the sides of the enclosure 130.
In various embodiments, the painting unit 14 sprays and/or dip paints or coats the items 20. In a particular embodiment, the painting unit 14 includes a container 140 to contain the paint. Depending upon the specifications for the item 20 and/or the paint, the item 20 may be dipped 1, 2, 3, or more time. In instances where the item 20 is to be dipped two times, the container 140 is configured to facilitate dipping two of the items 20, side by side. In this manner, the item 20 is dipped at a first position in the container 140, withdrawn from the container 140, advanced, and dipped at a second position in the paint container 140. When the item 20 is being dipped at the first position, a preceding item 20 may be dipped at the second position and while the item 20 is being dipped at the second position, a subsequent item 20 may be dipped at the first position. In this manner, the flow of items 20 through the painting unit may proceed efficiently and without delay. The paint container 140 is further configured to facilitate the use of a paint mixer 142, viscometer 144, and solvent supply 146. Following painting, the items 20 remain in the painting unit 14 sufficiently long enough for solvent to “flash off” and thereby reduce or substantially prevent the paint from blistering in the curing oven 16. For example, depending upon the solvent, the temperature of the painting unit 14, and the like, a flash off time of 10 minutes is sufficient to substantially prevent the paint from blistering. The viscometer 144 senses the viscosity of the paint. In response to the sensed viscosity of the paint, the solvent supply 146 is controlled to add solvent to the paint container 140. In a particular example, the paint mixer 142 includes a propeller-like mixing device disposed near the center of the paint container 140. Depending upon the solvent utilized in the paint, the paint mixer 142 is preferably operated by a pneumatic motor to avoid the hazards presented by running an electric motor in a solvent vapor atmosphere.
The painting unit 14 optionally includes an air knife 148. The air knife 148 directs a cone of air towards the item 20 as it is being withdrawn from the paint container 140. This air flow generates an air impingement that substantially prevents beads of paint from clinging to edges of the item 20. In a particular embodiment in which the items 20 are dipped twice, the air knife 148 includes a double circular configuration disposed on top of the container 140. In a particular embodiment, the item 20 is quickly lowered into the container 140 until submerged. The item 20 is withdrawn relatively more slowly than dipped. Preferably, the rate at which the item 20 is withdrawn is substantially constant.
To advance the items 20 through the painting unit 14, the item conveyer system employs the walking beam device 24 and a dipping actuator 150 configured to raise the item 20 over the container 140 and air knife 148. The walking beam device 24 is mounted to a support frame of the painting unit 14. The dipping actuator 150 includes a ball screw assembly driven by a servomotor, a reversing ball screw powered by a pneumatic gear motor, or other such suitable actuator. Suitable actuators include those that move at a controlled and consistent speed. In a particular example, the dipping actuator 150 is configured to move down about 15 inches in about 3 seconds and move back up in about 30 seconds. Depending upon the solvent utilized in the paint, the dipping actuator 150 includes an motor or other such actuator suitable for use with the solvent and/or the motor is substantially isolated from the solvent vapors. The length of the walking beam 24 is at least partially based upon the amount of time to flash off the solvent. For example, if each pitch of the walking beam device 24 is 6 inches and steps are performed once a minute, the walking beam device 24 is 5 feet long to achieve a ten minute flash off time.
Optionally, the painting unit 14 includes a ventilation system 152 to facilitate the removal of solvent vapors. In instances where the solvent is water or another essentially harmless solvent, the ventilation system 152 may be omitted. In other instances, the ventilation system 152 is configured to remove the vapors from the painting unit 14. In particular, the ventilation system 152 is configured to maintain the vapor level below a lower explosive limit for the particular solvent.
The painting unit 14 optionally includes a secondary containment system 154 to contain spilled and/or unused paint. Preferably, unused paint is transferred from the container 140 to the secondary containment system 154 within the confines of the painting unit 14 to minimize solvent vapors outside the painting unit 14.
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The curing oven 16 optionally includes a recirculation fan 160 to generate a recirculating airflow. In a particular example, the recirculation fan 160 generates about 1700 cubic feet per minute (“CFM”) of recirculation airflow. In general, the recirculation fan 160 is to generate a horizontal airflow around the items 20. The curing oven 16 optionally includes one or more automatic doors 162 for the items 20 to enter and exit the curing oven 16. If present, the automatic doors 162 are configured to reduce heat loss and/or contain vapors. The curing oven 16 optionally includes an exhaust fan 164. If present, the exhaust fan 164 is configured to remove some portion of vapor laden air from the curing oven 16. For example, the exhaust fan 164 is configured to turn on in response to the vapor content of the air in the curing oven 16 exceeding a predetermined maximum vapor content. In a particular example, the exhaust fan 164 includes a 68 CFM blower controlled via a vapor sensor.
Following curing, the items 20 are conveyed to another station or unloaded from the item carrier 22. For example, the items 20 are collected, conveyed to a device for further processing or conveyed directly to a construction line for integration into a device such as an airplane. As shown in
In a particular example, the release actuator 172 is configured to press the release 52. The unloading station 170 also optionally includes a gripper device 174 configured to serve a dual purpose. The gripper device 174 is configured to close above the item 20 after the item 20 has been released. If no obstruction is encountered (e.g., the connector 30 and item 20 have been released), the gripper device 174 is configured to open. If an obstruction is encountered (e.g., the connector 30 is not released), the gripper device 174 will clamp against the connector 30, in a particular example, a wire, and exert a downward force upon the connector 30 to facilitate extraction of the connector 30 and the item 20.
The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
