Method for spray forming metal deposits

Abstract

One method of the present invention relates to a method for spray forming metal deposits. The method is comprised of providing a ceramic substrate having a spraying pattern for receiving sprayed metal particles, spraying metal particles onto the spraying pattern to form a metal deposit on the spraying pattern for at least a first spray period, controlling the spraying step during the first spray period so that the temperature of the deposited metal particles increases at an average rate of less than or equal to about 15° per minute. The first spray period can be defined as lasting until the temperature of the deposited metal particles is at or about a steady state temperature. The steady state temperature is preferably in the range of about 330° C. to about 370° C.

Description

BACKGROUND OF INVENTION[0001] 1. Field of the Invention[0002] One aspect of the present invention generally relates to methods for producing prototype tools and, more specifically, to methods for spray forming metal deposits.[0003] 2. Background Art[0004] Spray forming has become an accepted technique for producing prototype tooling, i.e., dies and molds, in substantially less time than needed to make prototype tooling conventionally. The typical spray forming technique includes the following steps: (1) casting a ceramic substrate containing a spraying pattern about a mold containing a master pattern of the tool to be produced; (2) preheating the ceramic substrate; (3) spraying metal particles onto the substrate containing the spraying pattern; (4) allowing the sprayed metal particles to form a metal deposit having the general shape of the master pattern; and (5) separating the metal deposit from the ceramic substrate.[0005] During the early stages of the spraying step, a thin shell...

AI Technical Summary

Benefits of technology

0009] One aspect of the present invention includes providing a ceramic substrate having a spraying pattern for receiving sprayed metal particles, spraying metal particles onto the spray pattern to form a metal deposit on the spraying pattern for at least a first period, and controlling the spraying step during the first spray period so that temperature of the deposited metal particles increase at an average rate of less than or equal to about 15.degree. C. per minute. The first spray period lasts until the temperature of the deposited metal particles is at or about a steady state temperature. In accordance with the preferred embodiment, the controlling of spraying step comprise

Problems solved by technology

The significant thermal gradients can cause the thin shell to separate from the spraying pattern, causing surface imperfections, i.e., wrinkles and / or cracks, in the metal deposit.

In some cases, the surface imperfections are so extreme that the metal deposit is unsuitable for prototype tooling and must be scrapped.

Images