The invention relates generally to system and method for using an electrostatic tool.
Electrostatic tools spray electrically charged materials to more efficiently coat objects. For example, electrostatic tools may be used to paint objects. In operation, a grounded target attracts electrically charged materials sprayed from an electrostatic tool. As the electrically charged material contacts the grounded target, the material loses the electrical charge. Different materials lose electrical charges at different rates. Accordingly, some materials may not lose their electrical charge before more electrically charged material contacts the target. These residual charges may interfere with the overall coating and product finishes.
Certain embodiments commensurate in scope with the originally claimed invention are summarized below. These embodiments are not intended to limit the scope of the claimed invention, but rather these embodiments are intended only to provide a brief summary of possible forms of the invention. Indeed, the invention may encompass a variety of forms that may be similar to or different from the embodiments set forth below.
In a first embodiment, an electrostatic spray system, including an electrostatic tool configured to spray a material with an electrostatic charge, and a controller and wherein the controller is configured to change modes of the electrostatic tool, and wherein the modes are different processes that change the rate of material discharge, how much electrical charge is applied to the material, and when electrical charge is applied to the material.
In another embodiment, a system including an electrostatic tool controller configured to change operating modes of an electrostatic tool that discharges electrically charged material with slow rates of electrical charge decay.
In another embodiment, a method for producing a part with an electrostatic spray system, including powering an electrostatic tool with a power source, electrically charging a material, spraying the material with the electrostatic tool, changing the electric charge on the material while spraying, and discontinue spraying the material.
In another embodiment, a method for producing a part with an electrostatic spray system, including powering an electrostatic tool with a power source, electrically charging a material, spraying the electrically charged material with the electrostatic tool, gradually reducing the amount of electrically charged material sprayed, and discontinue spraying the material.
These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
One or more specific embodiments of the present disclosure will be described below. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.
When introducing elements of various embodiments of the present disclosure, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Any examples of operating parameters and/or environmental conditions are not exclusive of other parameters/conditions of the disclosed embodiments.
The present disclosure is generally directed towards an electrostatic system and methods for using the same. Specifically, the electrostatic system may fabricate products and coat objects using material with slow electrical charge decay (i.e., materials that once electrically charged do not easily lose charge). The slow electrical charge decay may interfere with proper product finishes and tolerances as the material starts to repel itself. The methods/processes described below advantageously enable an electrostatic system to fabricate products and coat objects using materials that have slow charge decay. For example, some of the embodiments described below may change the amount of electrical charge added to the sprayed material over time (i.e., periodically increase and decrease the electrical charge). This may advantageously allow the material to lose electrical charge by adding little or no charge for periods of time. In other embodiments, the electrostatic system may change the amount of sprayed material, thus giving the material more time to lose electrical charge by adding less overall charge to the coating or product.
In operation, the electrostatic spray system 10 uses the power source 14 to power an electrostatic tool 12. The electrostatic tool 12 may be a rotary atomizer or air atomizer capable of providing particle size less 10, 15, 20, 25, 50, 75, 100, 150, 200, or 250 microns (e.g., approximately between 1-20 microns, 3-18 microns, 5-15 microns). In operation, the electrostatic tool 12 electrically charges, atomizes, and sprays the material from the material source 22. The material may be a material used in medical products (e.g., a polymer, liquid silicon) or another kind of material with a slow electrical charge decay.
In the illustrated example, the electrostatic spray system 10 uses the voltage multiplier 16 to electrically charge the material inside the electrostatic tool 12. The voltage multiplier 16 receives power from the power source 14. The power source 14 may include an external power source or an internal power source, such as an electrical generator. The voltage multiplier 16 receives power from the power source 14 and converts the power to a higher voltage to be applied to the material in the electrostatic tool 12. More specifically, the voltage multiplier 16 may apply power to the material with a voltage between approximately 5 kV and 100 kV or greater. For example, the power may be at least approximately 15, 25, 35, 45, 55, 65, 75, 85, 95, 100, kV. As will be appreciated, the voltage multiplier 16 may be removable and may include diodes and capacitors. In certain embodiments, the voltage multiplier 16 may also include a switching circuit that changes the power between a positive and a negative voltage.
As shown in
The user interface 20 connects to and receives information from the controller 18. In certain embodiments, the user interface 20 may be configured to allow a user to adjust various settings and operating parameters based on information collected by the controller 18. Specifically, the user may adjust settings or parameters with a series of buttons or knobs 26 coupled to the user interface 20. In certain embodiments, the user interface 34 may include a touch screen that enables both user input and display of information relating to the electrostatic spray system 10. For example, the user interface 20 may enable a user to adjust the voltage supplied by the voltage multiplier 16, turn the voltage on/off, and adjust the amount of material sprayed by the tool 12 using a knob, dial, button, or menu on the user interface 34. Moreover, the user interface 34 may include preprogrammed operating modes for an electrostatic spray system 10. These modes may be processes that change the electric charge added to a sprayed material over a period of time or that change the amount of material sprayed by the electrostatic system 10. The modes may include periodically adding and completely removing electric charge from a sprayed material; progressively increasing and decreasing electric charge on sprayed material; removing all charge from material at an end portion of a spraying cycle; gradually reducing the electric charge on the sprayed material to nothing; or changing the amount of electrically charged material that is sprayed. An operator may activate one or more modes using a button, knob, dial, or menu 26 on the user interface 34. These preprogrammed modes may be a specific process for manufacturing a product, a specific step in a process, or may correspond to operating parameters for the electrostatic spray system 10 (e.g., voltage level, material discharge rate, time).
After receiving instructions from the controller 18, the electrostatic tool 12 applies an electric charge to material from the material source 22, represented by step 44. The electric charge will be specific to the mode (i.e., positive or negative charge and approximately between 5-100 kV). In the next step, the electrostatic tool 12 begins spraying the electrically charged material at a target (e.g., a mandrel), represented by step 46. As explained above, some materials once electrically charged do not lose charge quickly; that is, they have a slow rate of electrical charge decay. Accordingly, the material already on the object 24 may repel freshly sprayed electrically charged material, creating poor finishes or improper tolerances.
Advantageously, the process 40 allows the excessive electrical charge to dissipate. Specifically, electrostatic tool 12 may stop charging material while continuing to spray, represented by step 48. The process step 48 therefore sprays electrical neutral material, on top of electrically charged material on the mandrel 24. By spraying electrical neutral material the electrically charged material on the mandrel 24 has an opportunity to lose some or all of its electrical charge. The electrical charge may decay by traveling to ground through the mandrel, dissipating into the freshly sprayed electrically neutral material, and/or traveling through the air to the grounded electrostatic tool 12. The decay in electric charge reduces the ability of the material already on the target to repel the freshly sprayed material, therefore producing a product or coating with the proper finish and tolerance. Moreover, the time period for executing the step in step 48 may change depending on how fast the material loses electrical charge. For example, step 48 may last approximately 1 second to 100 or more seconds (e.g., 1-5, 3-10, 5-15, 10-100 seconds). The time period may be user adjustable, or auto adjustable based on feedback from electrical charge flowing through the target (e.g., mandrel). The process 40 may then stop spraying material, represented by step 50. Depending on the product or coating, the process 40 may repeat itself after a specific time period (e.g., flash period or partial cure period). For example, the process 40 may repeat multiple times (e.g., 1, 2, 3, 4, 5, 10, 15, 20 or more times) before producing a finished product or coating. Again, each iteration of the process 40 may first apply the electrically charged material (block 46) followed by applying the material without a charge to improve the top finish of the coating(s).
After receiving instructions from the controller 18, the electrostatic tool 12 applies electric charge to material coming from the material source 22, represented by step 64. The electric charge may be specific to the mode (i.e., positive or negative charge and approximately between 5-100 kV). The electric charge may be user adjustable, tied to the mode, and/or auto adjustable. The process 60 then begins spraying the electrically charged material using the electrostatic tool 12, represented by step 66. As explained above, some materials once electrically charged do not lose charge quickly; that is, they have a slow rate of electrical charge decay. Accordingly, the material already on the target 24 may repel freshly sprayed electrically charged material, creating poor finishes or improper tolerances.
Advantageously, the process 60 allows the excessive electrical charge to dissipate. Specifically, the electrostatic tool 12 may gradually reduce the electric charge applied to the material to zero over a period of time, represented by step 68. The rate at which the electrostatic tool 12 changes the electric charge depends on the material's ability to lose electrical charge. For example, if the material sprayed takes a long time to lose electrical charge, then the electrostatic tool may rapidly reduce the amount of electrical charge imparted to the material. For materials that may dissipate electric charge more quickly the rate may be slower (i.e., the electrostatic tool 12 may slowly reduce the amount of charge added to the material being sprayed). The process step 68, therefore, enables the material to lose electrical charge by reducing the amount of additional electrical charge over time. The decay in electrical charge may, therefore, reduce the ability of the applied material to repel, additional material thereby improving the finish and/or tolerances. As explained above, the electrical charge may decay by traveling to ground through the mandrel, dissipating into the freshly sprayed material that contains less electrical charge, and/or traveling through the air to the grounded electrostatic tool 12. The process 60 may then stop spraying material, represented by step 70. Depending on the product or coating, the process 60 may repeat after a specific time period (e.g., flash period or partial cure period). For example, the process 60 may repeat multiple times (e.g., 1, 2, 3, 4, 5, 10, 15, 20 or more times) before producing a finished product or coating.
After receiving instructions from the controller 18, the electrostatic tool 12 applies electric charge to material coming from the material source 22, represented by step 84. The electric charge will be specific to the mode (i.e., positive/negative charge and approximately between 5-100 kV). The process 80 then begins spraying the electrically charged material using the electrostatic tool 12, represented by step 86. As explained above, some materials once electrically charged do not lose charge quickly and may repel freshly sprayed electrically charged material, creating poor finishes or improper tolerances. Advantageously, the process 80 allows the electrical charge to dissipate while adding limited amounts of additional electric charge. Specifically, in step 88 of the process 80, the system 10 gradually reduces the amount of material sprayed over time while maintaining the electric charge on the material being sprayed. Accordingly, by spraying less material less charge is added over time, thus enabling the charge to decay. As the charge decays, the applied material is less likely to repel additional material and, therefore, produces an improved finish and/or tolerance. The process 80 may then stop spraying material, represented by step 90. Depending on the product or coating, the process 80 may repeat after a specific time period (e.g., flash period or partial cure period). For example, the process 80 may repeat multiple times (e.g., 1, 2, 3, 4, 5, 10, 15, 20 or more times) before producing a finished product or coating.
After receiving instructions from the controller 18, the electrostatic tool 12 adds an electric charge to a material as it sprays the material. The electric charge will be specific to the mode (i.e., positive/negative charge and approximately between 5-100 kV). More specifically, the electrostatic tool 12 will progressively increase and progressively decrease the charge on the sprayed material, represented by step 104. For example, the controller 18 may direct the electrostatic tool 12 to increase the voltage on the material from 5 to 100 kV over a period of time (e.g., 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, or more seconds) and to then decrease the voltage from 100 to 5 kV over another time period (e.g., 1, 2, 3, 4, 5, 10, 15, 20, 25, 30 or more seconds). The time period may be user adjustable, or auto adjustable based on feedback from electrical charge flowing through the target (e.g., mandrel). Furthermore, the controller 18 may direct the electrostatic tool 12 to repeat this step 104 multiple times (e.g., 1, 2, 3, 4, 5, 10, 20, 30 or more times). As explained above, when the material retains charge, it negatively affects the finish or tolerances of the final coating or product by repelling freshly sprayed material. Advantageously, the process 100 allows the electrical charge to dissipate during periods when the electrostatic tool 112 applies less electric charge to the sprayed material. Accordingly, by alternating or periodically increasing and decreasing the charge on the sprayed material, the charge on the material is able to decay so that the applied material does not repel additional material, thereby improving the finish and/or tolerance. The process 100 may then stop spraying material, represented by step 106. Depending on the product or coating, the process 100 may repeat after a specific time period (e.g., flash period or partial cure period). For example, the process 100 may repeat itself multiple times (e.g., 1, 2, 3, 4, 5, 10, 15, 20 or more times) before producing a finished product or coating.
After receiving instructions from the controller 18, the electrostatic tool 12 adds an electric charge to a material as it sprays the material. The electric charge will be specific to the mode (i.e., positive/negative charge and approximately between 5-100 kV). More specifically, the electrostatic tool 12 will cycle between adding charge and removing all charge from the sprayed material, represented by step 124. For example, the controller 18 may execute instructions that direct the electrostatic tool 12 to add a voltage to the sprayed material between 5-100 kV for a specific period of time (e.g., 1, 2, 3, 4, 5, 10, 15, 20, 25, 30 or more seconds) and to then remove all charged on the sprayed material for another time period (e.g., 1, 2, 3, 4, 5, 10, 15, 20, 25, 30 or more seconds). The time period may be user adjustable, or auto adjustable based on feedback from electrical charge flowing through the target (e.g., mandrel). Depending on the embodiment, the time period of spraying charged material may shorter or longer than the time period for spraying uncharged material. As explained above, if the material does not lose the added charge quickly the remaining charge may negatively affect the finish or tolerances of the final coating or product by repelling freshly sprayed material. Advantageously, the process 120 allows the electrical charge to dissipate by cycling between spraying electrically charged material followed by uncharged material in order to produce a coating or product with the proper finish and/or tolerances. The process 120 may then stop spraying material, represented by step 126. Depending on the product or coating the process 120 may repeat itself after a specific time period (e.g., flash period or partial cure period). For example, the process 120 may repeat multiple times (e.g., 1, 2, 3, 4, 5, 10, 15, 20 or more times) before producing a finished product or coating.
While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.
This application claims priority to and benefit of U.S. Provisional Patent Application No. 61/692,670 entitled “SYSTEM AND METHOD FOR USING AN ELECTROSTATIC TOOL”, filed Aug. 23, 2012, which is herein incorporated by reference in its entirety.
Number | Date | Country | |
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61692670 | Aug 2012 | US |