DRY ICE PARTS FINISHING SYSTEM

Abstract

Apparatus for treating parts to remove imperfections in the parts includes: a chamber; a rotatable basket within the chamber; a source of liquified cold fluid; a source of dry ice particles; a programmed controller to control rotation of the basket, activation of the liquified cold fluid, cycle times and activation of the dry ice particles. The controller is programmed to activate rotation of the rotatable basket, activate the source of liquified cold fluid and activate the dry ice particles to treat parts in the rotatable basket.

Claims

1. Apparatus for treating parts to remove imperfections in the parts comprising: a chamber; a rotatable basket within the chamber; a source of liquified cold fluid; a source of dry ice particles; a programmed controller to control rotation of the basket, activation of the liquified cold fluid, and activation of the dry ice particles; and, wherein the controller is programmed to activate rotation of the rotatable basket, activate the source of liquified cold fluid and activate the dry ice particles to treat parts in the rotatable basket.

2. The apparatus of claim 1, wherein the source of liquified cold fluid is selected from one or more of: liquid nitrogen or liquid CO2.

3. The apparatus of claim 1, wherein the source of dry ice particles is one or more of: dry ice blocks or liquified CO2.

4. The apparatus of claim 1, wherein the programmable controller first activates the rotatable basket, then activates the source of liquified cold fluid to deliver the cold fluid into the chamber and then activates the source of dry ice particles to cause the dry ice particles to impinge on and treat the parts within the basket.

5. The apparatus of claim 4, wherein the impingement of dry ice particles on the parts causes the removal of one or more of: flash or burrs on the parts.

6. The apparatus of claim 1, further comprising one or more nozzles operatively connected to the source of dry ice particles, and wherein the one or more nozzles is positioned to direct the dry ice particles into the interior volume of the basket.

7. The apparatus of claim 6, wherein the one or more nozzles is mounted into a wall of the chamber.

8. The apparatus of claim 6, wherein the rotatable basket is open in at least one end thereof, rotates about an axis of rotation, and the one or more nozzles are positioned to direct dry ice particles into the open end of the basket substantially along the axis of rotation.

9. A method for treating parts to remove imperfections in the parts comprising: providing a chamber; providing a rotatable basket within the chamber; providing parts whose imperfections are to be removed in the basket; providing a source of liquified cold fluid; providing a source of dry ice particles; providing a programmed controller to control rotation of the basket, activation of the liquified cold fluid, and activation of the dry ice particles; and, wherein the method comprises the controller activating rotation of the rotatable basket, activating the source of liquified cold fluid and activating the dry ice particles to treat parts in the rotatable basket.

10. The method of claim 9, wherein the sequence of activation is: rotation of the basket, activation of the source of liquified cold fluid and activation of the dry ice particles.

11. The method of claim 9, wherein the sequence of activation is: rotation of the basket, activation of the source of dry ice particles and activation of the liquified cold fluid.

12. The method of claim 9, wherein the dry ice particles impinge on the parts and remove one or more of: flash, burrs or other imperfections.

13. The method of claim 12, wherein the dry ice particles sublimate after impinging on the parts.

14. The method of claim 13, wherein the method is performed without the presence of traditional media.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] FIG. 1 illustrates a deflash chamber which incorporates the devices of the present invention.

[0037] FIG. 2 illustrates an interior view of the chamber of FIG. 1 illustrating the structure and operation of the present invention.

[0038] FIG. 3 illustrates an interior view of one wall of the chamber with parts of the device of the present invention shown.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0039] The present invention combines elements of both the “Cryogenic Deflashing and Deburring” method and the “Dry Ice Blasting” method by combining the beneficial elements of both into a new machine and technique that brings significant advantages over either prior method independently. By combining the two techniques, batch processing of large amounts of parts may be achieved, while at the same time the traditional media is eliminated. The stream of dry ice particles, once they impact on the part or parts, sublimate and turn to gas (vapor), thus leaving no residue as is the case with the types of traditional media discussed herein.

[0040] The present invention provides that the parts that require finishing may be placed into an insulated chamber (or compartment) that is equipped with a mechanized method for tumbling or otherwise presenting the parts to a blast stream of dry ice and that said chamber (or cabinet) be capable of achieving and maintaining a preprogrammed temperature in a closed and contained environment.

[0041] Temperature may be controlled and maintained by closed loop automated monitoring. The blasting stream may be in a permanent, semi-permanent (e.g. adjustable) or variable (over a random or preprogrammed pattern) location and may involve more than one source of dry ice delivery (e.g. opposite sides, multiple spray patterns, fixed and variable, etc.).

[0042] The pattern of dry ice may be adjustable as to the quantity of ice delivered, the size of the dry ice particles, the source of the dry ice, (e.g. liquid CO2 or solid CO2), as well as in its density of coverage and the pressure of application.

[0043] In certain applications, control of other factors (beside temperature) in the chamber may be incorporated, such as the air pressure, air flow direction and volume, air input, air input temperature, exhaust flow, exhaust location, etc.

[0044] Turning now to the drawing figures, FIG. 1 illustrates a perspective block view of a chamber which may be used in the practice of the present invention. The chamber may be an insulated chamber 10 which receives two cryogenic inputs: one (12) being a low temperature input in the form of liquid nitrogen (or other cryogen, such as CO2) which maintains the temperature of the parts being treated in a very cold condition or atmosphere, the other (14) being dry ice particles (which may be of uniform or variable sizes) that originate from either a solid source of dry ice or from a liquid CO2 source that changes state from a liquid or gas into a solid stream of dry ice particles. While both sources are shown mounted in the upper part of the chamber 10, it is to be understood that they may be mounted as desired. A more accurate view of a preferred embodiment is illustrated in FIG. 2 and described in detail below.

[0045] An exhaust system 16 removes gases after processing within the chamber 10. A programmable controller 17 may be incorporated to control such parameters as rates of turn of the perforated rotating drum (described above and below in greater detail in reference to FIG. 2) containing the parts to be treated, the quantity of liquid nitrogen to be introduced and the timing and quantity of dry ice impacting the parts to be treated. A door 15 may be provided to allow access to the interior of the chamber 10 and a drain 11 may be provided to drain any liquid residue from operations within the device 10.

[0046] Turning now to FIG. 2, this figure are further detailed representations of the chamber 10 from FIG. 1 but with the access door 15 being in an open state. FIG. 2 shows a drum or mesh basket 18 mounted in the chamber 10 in which the drum may be made to rotate about axis 20 in direction 21, although it could also rotate in the opposite direction. The drum or mesh basket 18 may be driven to rotate by a suitable motor and the basket may be supported on rollers 22 mounted within the chamber and engage slotted rails 23, although the present invention is not limited to this just-described support and rotation system. The drum is perforated as seen in reference numeral 25 to allow nitrogen liquid turned gas to permeate the rotating drum or basket and any parts 27 contained therein. The parts 27 to be treated are placed in the interior of the drum/basket. The permeations or holes in the mesh basket may be suitably sized such that nitrogen may permeate the basket and the parts therein, but also be small enough so that the parts being treated do not fall through the holes. Another consideration is to construct the holes such that burrs, flash and other imperfections which are removed from the parts may fall to the bottom of the chamber for removal. While it cannot be seen in FIG. 2, at least one “end” of the drum/basket is “open” as will be explained in connection with FIG. 3.

[0047] Further, in FIG. 2 is shown the dry ice supply 14. The dry ice supply, as mentioned, may be a known device which crushes or slices a dry ice block or dry ice cubes to a predetermined size and then “shoots” the particles thus formed through conduit 19 and through to nozzle 29. It is to be understood that nozzle 29 may be of any suitable size or material to deliver the particles. Further, multiple nozzles may be employed depending on the coverage desired, the particular parts to be treated, etc. The nozzle or nozzles may be adjustable in direction to suit the particular set-up and parts types to be treated, or may even be movable so that the nozzles(s) and thus the direction(s) of dry ice flow may be adjusted and varied to suit the particular treatment regimen. It is also to be understood that instead of the dry ice device that employs dry ice, a CO2 canister may be provided in the same manner to conduit 19 and nozzle 29.

[0048] The nozzle 29 is shown in FIG. 2 as mounted to enter an aperture in the chamber 10. The nozzle may be designed to enter the chamber but not into the basket or may be designed to project into the basket itself, it being understood that the drum/basket is at least partially open so that it may receive the nozzle 29 or at least a spray of dry ice particles emanating from the nozzle into the drum/basket.

[0049] FIG. 3 is similar to FIG. 2 except that the basket has been removed to show the interior portions of the chamber 10 of the present invention. Liquid nitrogen (or another suitable cryogen) may be delivered through access 12. The drum/basket may be rotated by way of a basket drive (not shown) which is in turn associated with a motor (also not shown). A dry ice entrance 28 is cut through the chamber wall. The dry ice entrance 28 receives the nozzle 29 connected to a source of dry ice particles. Because, as mentioned, the “end” of the drum/basket is “open”, the dry ice particles “shot” or “blasted” from the nozzle 29 will impinge on the moving parts in the drum/basket and remove burrs, flash and other imperfections in or on the parts, which burrs, flash and other imperfections will fall through the holes or mesh in the basket and to the bottom of the chamber.

[0050] Thus, in operation, parts to be treated may be placed into the chamber 10 and the drum/basket 18, and the basket rotated under the control of the programmable controller 17. Then, the source of liquid nitrogen 12 may be activated so that a flow of liquid nitrogen (which will morph to a very cold gas) will envelope the parts 27 rotating in the basket 18. After that the dry ice supply 14 may be activated, again under the control of the programmable controller 17, so that dry ice particles will impinge on the parts 27 and thus remove burrs, flash or other imperfections from the parts. The burrs, flash or other imperfections will be expected to fall through openings in the basket and all to the bottom of the chamber to be removed at some juncture, thus leaving the parts free of burrs, flash or other imperfections but also the traditional media of the prior art devices. It is to be understood that the sequence of activating rotation of the basket, activating the liquid nitrogen source and activating the dry ice source may be sequenced in any suitable manner or order of activation.

[0051] Once the operation has been completed, the parts are removed. No cleaning of media from the parts is required with the present invention. While FIGS. 2 and 3 show the drum/basket horizontally disposed, it is to be understood that it may be disposed at any other suitable angle so long as the nozzle is “aimed” at the open end of the drum/barrel so that the full effects of the dry ice blasting may be applied to the parts.