During the casting process of a cylinder head, for example, a sand core is placed in a die to form intricate passages required of the specific casted piece. After producing the casting, the sand is removed from the internal cavities of the casting. Current methods to verify the internal condition of sand remaining in the casting include manually striking the casting and making a judgment based on quantity, color and conditions of the sand that falls from the casting. The current method is based on operator evaluation and can be prone to human mistakes and varying interpretations of standards.
An example of a method for testing casting quality that can overcome at least one of the aforementioned shortcomings includes collecting sand that has fallen from an internal cavity of the casting at a collection area. The collection area includes a screen and a pad. The method further includes capturing a first image of sand that has fallen onto the pad and analyzing the first image to determine an amount of black sand that has fallen onto the pad. The method further includes capturing a second image of sand that has been retained on the screen and analyzing the second image to determine an amount of black sand chunks retained on the screen.
An example of a black sand check machine includes a stand for supporting a casting, a hammer positioned with respect to the stand for striking the casting to dislodge sand from the casting, a collection area below the casting supported by the stand for collecting sand dislodged from the casting, and a camera positioned with respect to the collection area for capturing images of sand that has fallen from the casting. The collection area includes a screen and a pad. The camera is positioned for capturing images of sand that has fallen from the casting onto at least one of the screen and the pad.
Another method for testing casting quality includes providing a sand sample from a casting on a screen supported by an underlying surface; capturing a first image of the sand sample on the underlying surface; analyzing the first image for black sand coverage; removing the underlying surface; capturing a second image of the sand sample retained on the screen; and analyzing the second image for black sand coverage.
The stand 12, which supports the cylinder head 14 (or other casting), can be made from a metal frame having an opening that allows sand that has fallen from the cylinder head 14 to fall towards the collection area 18. A gripper 32 can also support the cylinder head 14 and be used to move the cylinder head to the stand 12 and to carry the cylinder head 14 away from the stand. The gripper 32 and the stand 12 minimize the physical handling of the cylinder head 14 by an operator who is to check the casting quality. In the illustrated embodiment, the cylinder head 14 is positioned in a vertical position with respect to the stand 12 with a large water port of the cylinder head 14 pointing downward, i.e., towards the collection area 18. The cylinder cavities (not depicted in
The hammer 16 can be hydraulically or pneumatically actuated. The force applied by the hammer 16 onto the cylinder head 14 can approximate the force of a 16-ounce hammer swung by a line worker. An example of such a force is between about 10 lbf and about 20 lbf. Even though only one hammer 16 is shown, multiple hammers can be provided. The cylinder head 14 can be struck in multiple locations on the cylinder head 14 using the multiple hammers. The cylinder head 14 can also be struck a single instance or multiple times. The force at which the hammer 16 contacts the cylinder head 14 is chosen to be a great enough force enough to dislodge any black sand that might be stuck within the internal passages of the cylinder head 14 without cracking the cylinder head 14.
The collection area 18 is positioned below the cylinder head 14 supported by the stand 12 and is for collecting sand dislodged from the cylinder head 14. The collection area 18 includes the funnel 22, which is disposed above the screen 24 and the pad 26. The funnel 22 directs the sand that has fallen from the cylinder head 14 toward the screen 24 and the pad 26. The screen 24 is disposed above the pad 26 in the illustrated embodiment. The screen 24 can be a wire mesh screen having two millimeter openings (apertures) and a wire diameter of 2 mm. The size of the openings can be dependent upon the casting that is being checked with the black sand check machine 10. The pad 26, which is disposed underneath the screen 24, can be a white flat (planar) pad. By making the pad 26 white in color, black sand will register in images captured by the camera 28 of the white pad while white sand can be ignored. An actuator 34 can be provided to move the pad 26. For example, the actuator 34 can allow the pad 26 to pivot such that sand that has fallen onto the pad can drop onto a conveyor 36 to be taken away from the black sand check machine 10.
The camera 28 is schematically depicted as positioned with respect to the collection area 18 for capturing images of sand that has fallen from the cylinder head 14 onto at least one of the screen 24 and the pad 26. The camera 24 can be similar to industrial CCD/CMOS sensor type cameras and include a lens with a built-in LED ring light, which can emit light of the desired color for the application (for example, red, blue or white). The camera 28 includes a lens 30, which can be situated directly above the screen 24 and/or the pad 26. The screen 24 can rest on and/or be supported by the pad 26. The camera 28 can be set at an exposure to wash out the screen 24 when capturing images of sand that has fallen from the cylinder head 14.
The black sand check machine 10 further includes a processor 38 in electrical communication with the camera 28. The processor 38 is configured to process images captured by the camera 28 and can also communicate with a display 42 to display the captured images. The camera 28, the processor 38, and the display 42 can be provided to analyze images to determine the quality of the casting of the cylinder head 14 in a manner that will be described in further detail below.
A method for testing quality of a casting will be described with reference to
With reference to
Sand that is knocked loose falls into the funnel 22 and is collected, at 104, for evaluation. The sand that is collected has fallen from internal cavities of the cylinder head 14 and is collected at the collection area 18. As mentioned above, the collection area 18 can include the funnel 22, the screen 24, and the pad 26. Collecting fallen sand from the cylinder head 14 can also be referred to as providing a sand sample from a casting on a screen, such as the screen 24, supported by an underlying surface, such as the pad 26.
The method for testing quality of a casting further includes setting the exposure on the camera 28 to wash out the screen 24, more particularly the wires of the screen, in the collection area 18. In other words, at 106, the exposure of the camera 28 is set such that the images captured by the camera do not include the individual wires that make up the screen 26 in any images where the screen 24 has been washed out. Since the captured image does not include the wires that make up the screen 24, this allows for a more accurate depiction of black sand that has fallen from the cylinder head 14 onto the white pad 26.
The camera 28 then captures a first image at 108. The first image is used to evaluate the amount of black sand present in the collected sand sample. Since the exposure has been set to wash out the screen 24, which is disposed above the white pad 26, the black sand registers in the first image captured at 108 while white sand is ignored. An example of such a first image is shown in
After capturing the first image at 108, the first image is then analyzed at 112. With reference to
With reference back to
The method further includes capturing a second image of the screen 26 at 116. An example of such a second image is shown in
The second image is then analyzed at 118. Analyzing the second image can include measuring a number of black sand chunks retained on the screen 24. With reference to
A method for testing quality of a casting and a black sand check machine have been described above with particularity. Modifications and alterations will occur to those upon reading and understanding the preceding detailed description. The invention, however, is not limited to only the embodiments described above. Instead, the invention is broadly defined by the appended claims and the equivalents thereof. Also, it will be appreciated that various of the above-disclosed and other features and functions, or alternatives or varieties thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.