Heated blades for wax melting
A wax tree assembly heating system for heating wax on the surface of a wax component is provided. The system includes an elongated bar of heat conducting material, having a heating surface, and a heating element for heating the heating surface. The heating surface is configured to contact a wax component, such as a wax runner or a gate of a wax pattern, and has a space for retaining molten wax when the heating surface contacts a surface of the wax component. In another embodiment, the wax tree assembly heating system has a plurality of raised heating surfaces that are configured for producing molten wax on a plurality of areas on one or more surfaces of at least one wax component. Additionally, an electrical circuit is provided which includes a heating element and a temperature controller to control the temperature at which wax is melted.
This application is a continuation of co-pending parent U.S. patent application Ser. No. 10/601,932, filed Jun. 23, 2003, entitled “HEATED BLADES FOR WAX MELTING,” and accordingly priority for this continuation application is claimed from U.S. patent application Ser. No. 10/601,932. The entire disclosure of U.S. patent application Ser. No. 10/601,932 is incorporated herein by reference.
BACKGROUND OF THE INVENTION1. Technical Field
This invention relates to the production of wax trees for casting and, more particularly, to blades or knives for heating the surfaces of wax runners and wax pattern gates in a process for attaching a wax pattern gate to a wax runner.
2. Background Information
The Lost Wax Process is a long established process for casting. In the practice of the Lost Wax Process a wax pattern of a part to be cast is molded in wax. When the wax pattern is molded, a pattern gate is molded with the wax pattern in one piece. Wax runners are also molded separately. Wax runners are usually at least one branch, frequently with flat surfaces and two ends. Some wax runners have circular cross sections and, thus, do not have either flat surfaces or edges. At one end of the runners, there is a head, and, at the other end, there is a tail. A pour cup may be located at the head. The wax pattern gates are affixed to the wax runners to form a wax tree. To do this, both the attaching surface of the wax pattern gate and the surface of the wax runner need to be heated sufficiently to melt wax to permit fusion. Once the wax patterns are affixed to the wax runner, a wax tree has been formed, and then ceramic material is placed on the wax tree. Once the ceramic has hardened, it is heated causing the wax to flow out of the ceramic. The ceramic thus forms a mold into which the molten metal is poured to produce the desired part.
In recent times, much of the Lost Wax Art has been substantially automated. In the patent application of Ludwig, et al, entitled Process and Apparatus for the Assembly of Wax Trees, U.S. patent application Ser. No. 10/304,840, now U.S. Pat. No. 6,910,519, assigned to the same assignee, an advanced process and apparatus is taught for automating the fusion of wax gates of wax patterns to a wax runner. A heated blade is used to heat the pattern gates and the wax runner. The heated blade, the pattern gates and the wax runner are all manipulated by robotics. However, the fusion of wax pattern gates to a wax runner has been traditionally a manual operation performed by heating putty knives on a Bunsen Burner to melt the surface of the wax runner and the end of the pattern gate.
In the automated process, the wax runners are held by a head stock and a tail stock in a runner station. The wax runner is also heated in the automated process so that a plurality of wax patterns can be affixed to the wax runner at one time.
Maintaining a wax runner in a perfectly flat position when attaching the wax patterns is a most desirable goal, but unfortunately is not readily attainable. As a result, portions of the wax runner are penetrated more deeply by the heated blade than other portions. Excess molten wax is a result of excessive melting, and, should the excessive melted wax run over the side of the wax runner, the wax runner and the wax patterns attached to it are not useable, resulting in lost product.
In heating the wax gate and the wax runner, the temperatures of heating the wax can become sufficiently high as to exceed the flash point of the wax causing it to give off fumes which are considered to be a health hazard.
Therefore, it is highly advantageous to provide a blade for heating a wax runner that prevents molten wax from running over the edge of the wax runner, and it is also highly desirable to control the temperature of the heated blade for melting wax on the wax pattern gate and wax runner to avoid the emission of fumes.
SUMMARY OF THE INVENTIONThe present invention provides, in a first aspect, a wax tree assembly heating system for heating a wax surface. The system comprises an elongated bar of heat conducting material having a heating surface and means for heating the heating surface. The heating surface is configured to contact at least one of a pattern gate and a wax runner, and the heating surface has a space for molten wax to be retained when the heating surface contacts a wax surface of at least one of the pattern gate and the wax runner.
In a second aspect in accordance with another embodiment, the present invention provides a wax tree assembly heating system for producing molten wax on a plurality of areas on one or more surfaces of at least one wax component. The system comprises the following features: an elongated bar of heat conducting material having a plurality of raised heating surfaces configured to contact at least one of a pattern gate and a wax runner; and means for heating the raised heating surfaces.
The present invention provides, in a third aspect, a method of heating wax on a surface of a wax component using a wax tree assembly heating system having a heating surface in preparation for fusing the wax component to another wax component in assembling a wax tree. The method comprises providing an elongated bar having a heating surface configured to provide a space for molten wax to be retained when the heating surface contacts a wax component, heating the heating surface, and temporarily positioning the heating surface of the elongated bar in contact with the wax component.
These, and other objects, features and advantages of this invention will become apparent from the following detailed description of the various aspects of the invention taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Table 1 below provides a list of reference numbers found in the accompanying drawings.
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It is to be understood that the drawings and description matter are in all cases to be interpreted as merely illustrative of the principle of the invention, rather than as limiting the same in any way, since it is contemplated that various changes may be made in various elements to achieve like results without departing from the spirit of the invention or the scope of the appended claims.
Claims
1. A wax tree assembly heating system for heating a wax surface comprising:
- an elongated bar of heat conducting material having a heating surface configured to contact at least one of a pattern gate and a wax runner, said heating surface having a space for molten wax to be retained when the heating surface contacts a wax surface of the at least one of the pattern gate and the wax runner; and
- means for heating the heating surface.
2. The system of claim 1, wherein the heating surface comprises a recessed area for retaining molten wax.
3. The system of claim 2, wherein the recessed area comprises a concave surface.
4. The system of claim 1, wherein the heating surface comprises at least one groove.
5. The system of claim 4, wherein a width of a cross section of the at least one groove becomes smaller at a greater depth of the at least one groove.
6. The system of claim 4, wherein the at least one groove has a v-shaped cross section.
7. The system of claim 1, wherein the means for heating the heating surface comprises an electrical heating element.
8. A wax tree assembly heating system for producing molten wax on a plurality of areas on one or more surfaces of at least one wax component comprising:
- an elongated bar of heat conducting material having a plurality of raised heating surfaces configured to contact at least one of a pattern gate and a wax runner; and
- means for heating the raised heating surfaces.
9. The system of claim 8, wherein at least one of the raised heating surfaces comprises a recessed area for retaining molten wax when the raised heating surfaces contact the at least one of the pattern gate and the wax runner.
10. The system of claim 9, wherein the recessed area comprises a concave surface.
11. The system of claim 8, wherein at least one of the raised heating surfaces comprises at least one groove for retaining molten wax when the raised heating surfaces contact the at least one of the pattern gate and the wax runner.
12. The system of claim 11, wherein a width of a cross section of the at least one groove becomes smaller at a greater depth of the at least one groove.
13. The system of claim 11, wherein the at least one groove has a v-shaped cross section.
14. The system of claim 8, wherein the means for heating the raised heating surfaces comprises an electrical heating element.
15. The system of claim 8, wherein at least one of the raised heating surfaces conforms to a shape of the pattern gate to be fused to the wax runner in assembling a wax tree.
16. The system of claim 8 further comprising a temperature controller for controlling the means for heating.
17. The system of claim 16 further comprising a temperature sensor, wherein the temperature sensor provides a signal indicating a temperature of the elongated bar to the temperature controller.
18. A method of heating wax on a surface of a wax component using a wax tree assembly heating system having a heating surface in preparation for fusing the wax component to another wax component in assembling a wax tree, wherein the method comprises:
- providing an elongated bar having a heating surface configured to provide a space for molten wax to be retained when the heating surface contacts a wax component;
- heating the heating surface; and
- temporarily positioning the heating surface of the elongated bar in contact with the wax component.
19. The method of claim 18, wherein the heating surface comprises a plurality of raised areas configured to provide spaces for molten wax to be retained when the heating surface contacts the wax component.
20. The method of claim 19, wherein the wax component comprises one of a wax runner and a wax pattern, and at least one of the plurality of raised areas conforms to a shape of a gate of the wax pattern to be fused to the wax runner.
Type: Application
Filed: Oct 17, 2005
Publication Date: Feb 16, 2006
Inventors: Raymond Puffer (Watervliet, NY), Bruce Phipps (Millbrook, NY), Daniel Walczyk (Brunswick, NY), Rory MacKean (Milford, NH), Jason Chalfant (Newhall, CA), Keith Hedrick (Modena, NY)
Application Number: 11/252,068
International Classification: B22C 7/02 (20060101); B22C 9/04 (20060101);