Patent Publication Number: US-2011068070-A1

Title: Container and process for cleaning and inspecting parts

Description:
FIELD OF THE INVENTION 
     This invention relates generally an article of manufacture and a process for cleaning and inspecting parts exposed to various chemicals during manufacturing. 
     BACKGROUND OF THE INVENTION 
     A variety of newly machined metal and plastic parts must be cleaned during the manufacturing process to remove residues of oil, grease, penetrant and other materials. Typically total immersion systems convey parts through a series of cleaning stations that employ cleaning, agitating and spraying to dislodge chemicals and particles. 
     Parts to be washed are generally placed into containers and oriented based on the greatest number of parts per container dimensions without regard for other important factors such as penetrant removal. In a typical washing process turbulation moves solution over, under, around and through a part. Manifolds with jets or eductors direct a turbulent liquid flow over a working zone. 
     One of the functions of industrial parts washing is to remove penetrant used in inspection processes. Fluorescent penetrant inspection (FPI) is a widely applied method used to detect casting and forging defects, cracks, and leaks in new products, and fatigue cracks on in-service components surface breaking defects in non-porous materials such as metals, plastics, or ceramics. FPI is based upon fluid penetration into clean and dry surface-breaking discontinuities through capillary action. Penetrant may be applied to the test component by dipping, spraying, or brushing. After adequate penetration time has been allowed, the excess penetrant is removed and a developer is applied. The developer draws penetrant out of the flaw where an indication becomes visible to an inspector under various lighting conditions. 
     The effectiveness of the inspection depends on the removal of penetrant prior to application of the developer. The penetrant must be thoroughly removed except for that which reveals any defects in the parts. The contact points between the parts and the container are a problem for penetrant removal. Those part areas or points in contact with the container cannot be effectively spray rinsed without overwashing the non-contact surfaces. 
     SUMMARY OF THE INVENTION 
     According to an aspect of the present invention a container comprises a plurality of spring-like wires having wave patterns forming a part support that minimize contact points between the container and one or more contained parts when the container is subjected to a vibration causing the wires and the parts to move, thereby eliminating any fixed contact points between a part and the supporting part support. 
     Another aspect of the invention is a process for removing penetrant from parts comprising: placing one or more parts having a penetrant thereon applied in a container having spring-like wire with wave patterns forming a part support; oscillating the container during a cleaning process thereby compressing and expanding one or more spring-like wires thus exposing part surfaces and removing the penetrant from the parts. 
     In yet another aspect the invention comprises: a container constructed of stainless steel rods having a wire mesh wave patterns that allow selected parts to flex and reflex in conjunction with an oscillation of the container and a pressured liquid spray on the parts. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is best understood from the following detailed description when read in connection with the accompanying drawing. The various features of the drawings are not specified exhaustively. On the contrary, the various features may be arbitrarily expanded or reduced for clarity. Included in the drawing are the following figures: 
         FIG. 1  is a perspective view of a parts washing container or basket in accordance with an embodiment of the present invention. 
         FIG. 2   a  is a perspective view of a parts washing container in accordance with an embodiment of the present invention. 
         FIG. 2   b  is a perspective view of a spring-like wire having wave patterns in accordance with an embodiment of the present invention. 
         FIG. 2   c  is a perspective view of a spring-like wire having wave patterns in accordance with an embodiment of the present invention. 
         FIG. 3   a - d  is a diagram of a parts penetrant application and inspection cycle in accordance with an embodiment of the present invention. 
         FIG. 4   a  is a block diagram of a parts washing system in accordance an embodiment of the present invention. 
         FIG. 4   b  is a top elevation view of a washing system in accordance with the prior art. 
         FIG. 4   c  is a perspective view of a washing system and a container in accordance with an embodiment of the present invention. 
         FIG. 5  is a block diagram of a process for washing parts and preparing parts for an inspection in accordance an embodiment of the present invention. 
         FIG. 6   a  is a front view of a spray chamber spraying parts from top jet sprayers. 
         FIG. 6   b  is a front view of the spray chamber spraying parts with middle spray jets. 
         FIG. 6   c  is a front view of the spray chamber spraying parts with bottom spray jets. 
         FIG. 7  is a side view of a parts washing container or basket having support wires of another configuration. 
         FIG. 8  is a detailed view of top and bottom support wires according to this invention. 
         FIG. 9  is a front view of the basket of  FIG. 7 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a perspective view of a parts a washing container  100  that provides cleaning utilizing washing, rinsing and drying according to an embodiment of the present invention. The container  100  includes a top portion  102 , a bottom portion  104 , and spaced-apart side portions  105 . The top portion  102 , bottom portion  104 , and side portions  105  are open for permitting the passage of fluid and debris therethrough. The container  100  has support frame side members  107 ,  109  and vertical side members  115  that both support and enclose the container. Members  111 ,  113  provide bottom support. A member  103  provides a means of maneuvering the container  100 . A series of spring-like wires  110  in the shape of one or more wave patterns provide a part support for the parts  120  during cleaning. Each end of the spring-like wires  110  are fixed to two opposing ends of the frame side portions  105  at node  3 ′. In one non-limiting embodiment of the invention the spring-like wires  110  having wave patterns, the top portion  102 , bottom portion  104 , and spaced-apart side portions  105  are formed from stainless steel. 
     A shown in  FIG. 1  contact points between parts  120  and the container  100  pose a problem for removal of chemicals such as penetrant, since sprays and other washing techniques cannot reach the locus of points between the part and the member that supports the part in the container  100 .  FIG. 2   a - FIG. 2   c  show an aspect of the present invention where spring-like wires  110  have wire wave patterns that minimize contact points between the container  100  and the parts  120  to be cleaned. By way of example and not limitation, the spring-like wires  110  wave patterns may be generally serpentine, sawtooth or sinusoidal.  FIG. 2   b  illustrates a nominally serpentine form.  FIG. 2   c  is a view of a spring-like wire having wave patterns nominally in a sawtooth form. The minimal contact at points such as  1 ′,  2 ′ between the wires  110  and the parts  120  offer friction levels insufficient to retain the parts in position when for example a force from a mechanical means or from a liquid spray is applied. Typically the wires  110  move both longitudinally and transversally due to forces F 1  transmitted to the wire  110  at node  3 ′ i.e. the connection between the wires  110  and side portion  105 ; or due to forces F 2  applied to the part  120 , as by way of example liquid spray sufficiently forceful to move the part  120  from its position at  1 ′,  2 ′. 
     FPI reliability is dependent upon its removal in areas where no defects appear. Therefore a thorough cleaning in every area of a part  120  is essential. The entire surface of a part  120  is cleaned to remove any dirt, paint, oil, grease or any loose scale that could either keep penetrant out of a defect, or cause irrelevant or false indications. The goal of this step is a clean surface where any defects present are open to the surface, dry, and free of contamination.  FIG. 3   a - FIG. 3   d  illustrates a part  120  in cross section A having a defect  122  that does not appear at the surface  121  of the part  120 . It is shown in a cross section A to illustrate one manner in which the defect such as a crack may manifest.  FIG. 3   b  shows the first step in the inspection process where a penetrant  123  is applied to the part  120 . The penetrant may be by way of example a water-washable, solvent-removable, lipophilic postifiable, or hydrophilic post-emulsifiable.  FIG. 3   c  shows that after an adequate penetration time the excess penetrant  124  is removed. In  FIG. 3   d  a developer  126  is applied to the part  120 . Nominally after a 10 minute development time, the developer  126  draws the penetrant  123  out of the defect  122  where it becomes visible under light  127 . A colored stain indicates the position and type of defect on the surface  121 . Typically inspection is observed in visible light with intensity in the range of 100 foot-candles for visible dye penetrant. Ultraviolet (UV-A) radiation of 1,000 microwatts per centimeter squared is also a common illumination as is low ambient light levels in the range of less than 2 foot-candles for fluorescent penetrant examinations. 
     Referring now to  FIG. 4   a , the container  100  is loaded into the washing system  300  having penetrant applied and unloaded when the washing cycle is complete and parts  120  are ready for development of the penetrant and the inspection. System  300  includes an immersion tank (not shown) and automatic transport elevators (not shown) as required. The transport elevator tanks place the container  100  into and out of the processing zones such as  301 ,  302 . Using only water or emulsifier as the cleaning agent at low temperatures the parts  120  are thoroughly cleaned but not overwashed. The factors governing this stage are temperature, flow, pressure, spray pattern, time, and container  100  configurations including the spring-like wires  110  part support. Each stage of cleaning is controlled within the system  300  by a programmed controller  321  that provide control signals to the electromechanical devices (not shown) that transport the container  100  and turn on and off processes at the various cleaning zones such as  301 ,  302 . A mixing valve (not shown) may be used to maintain consistent hot water within the limits set by the specifications on penetrant removal. Multiple spray rinsing zones may be incorporated within the processing zones  301 ,  302 . Each zone  301 ,  302  may have an independent pressure and flow control. Each spray pattern is defined by nozzle types and their locations to provide the required coverage as dictated by the specific parts  120  and container  100  configurations. 
     Referring to  FIG. 4   a  the washing system  300  has means for creating turbulence within at least one of the plurality of wash zones  301 ,  302 . The washing system  300  further includes drying means (not shown) for the parts being discharged from a rinse tank. Additionally the washing system contains means to oscillate or vibrate  325 , a plurality of filtering means such as filter  330 , including filter pump  332  for recirculating the cleaning solution from zone  301  wash tank through filter  330  and thereafter returning filtered wash solution to a wash tank that would be free from particles of debris. 
     Container  100  is loaded with parts  120  and placed in the washing system  300  where it is typically gently oscillated during a cleaning process cycle. The oscillation means may be provided by the mechanical vibrator or agitator  325  that provides a force (e.g., through a transducer) to the wire through a connection between the wires and a frame member receiving the applied force. Means to create and transmit such forces are well known to those of ordinary skill in the mechanical arts. The period, frequency and amplitude of the agitator  325  vibrations may be controlled by the programmed controller  321  by providing control signals to electromechanical devices (i.e., transducers) also by means well known to those of ordinary skill in the mechanical arts. The oscillating motion causes the spring-like wires  110  having wave patterns to flex and reflex. This contributative motion causes the parts  120  to slightly move thereby allowing complete washing of penetrate at contact points. Such contact points in the prior art washing systems are not capable of being exposed to the washing medium due to the container design and a static processing mode. The current invention by virtue of the spring-like wires  110  and the oscillation working in combination insures that every part of the part  120  surface is exposed to the washing medium. 
     In  FIG. 4   c , the container  100  is shown in the position to receive the spray nozzles  310 . The overall configuration of the container  100  is custom made to minimize shadowing during spraying utilizing the spray nozzles  310 . The container  100  may remain stationary or move through washing zones  301 ,  302  relative to washer system  300 . Each zone  301 , 302  is preselected for long or short stroke oscillation during the cycle. The programmed controller executes cycle times to “fire” each zone  301 ,  302  for a precise exposure time. The zones are fired in sequence and cycled through in multiple “rollovers”. By way of example, the water rinse cycle produced may be fast, gentle and accurate to balance the required cleaning variables to remove the penetrant while preventing over washing. 
     Referring again to  FIG. 4   c  when the container is inserted into the washing system  300  it is positioned slightly above the cleaning by spray nozzles  310 . In one embodiment, a first step in the cleaning process occurs where the container  100  of parts is subjected to a cleaning spray that contains the spray solution, for a period of between 20 and 30 seconds where one or more spraying nozzles  310  are directed at a 30 to 45 degree angle to pre cleans the parts to remove loose particles of debris. 
     In one embodiment a V-jet nozzle or a full cone of liquid from a plurality of sides, sprays the parts as the container tray oscillates while above the liquid in front of sprays. Each cycle is pre-selected for stroke length and speed during oscillation. Programmed controlled cycle times are used to “fire” each zone for preset exposure times. This provides constantly changing flow patterns to the process and conserves water consumption. 
     The invention herein also includes a process  500  for washing parts  120  comprising: placing  510  one or more parts  120  having a penetrant thereon applied in container  100  having spring-like wire with wave patterns forming a part support; oscillating  520  the container  100  during a cleaning process thereby compressing and expanding  530  one or more spring-like wires thus exposing part surfaces and removing  540  the penetrant from the parts. 
     Referring to  FIG. 6  there is shown a spray chamber  600 , which chamber  600  accommodates a parts washing container or basket  610 . The basket  610  has, as shown, serpentine or wave-like support wires  611  which support a part  612  to be cleaned. As shown, the spray chamber has a plurality of spray jets or nozzles located throughout. As seen in  FIG. 6  there are top spray nozzles or jets  606  and  607 , middle spray jets  601  and  604  and bottom spray jets  602  and  603 . 
     As will be noted the basket  610  is moveably supported as the part  611  is subjected to multiple spray exposure in a predetermined sequence as will be explained. 
     Thus  FIG. 6   a  shows the basket  610  in a top position in chamber  600  where spray jets  606  and  607  operate to spray or clean the part  612 . It is noted while a single part  612  is shown the basket holds multiple parts. While two top spray jets  606  and  607  are shown additional jets or nozzles may be employed. 
     In  FIG. 6   b  the basket  610  is moved to a middle position where jets  601  and  604  are operated to further clean the part. 
     In  FIG. 6   c  the basket  610  is moved to a lower or bottom position, where jets  602  and  603  are operated. 
     As can be ascertained the basket  610  is moved by the chamber apparatus and during each position different nozzles or jets are activated. 
       FIG. 7  shows an end view of the container or basket  700  having the part support wires  701 . 
       FIG. 8  shows the wave-like curvature of the top wire  800  and bottom wire  801  configuration. It is noted that the support wire has multiple peaks. As seen in  FIG. 8 , there are 5 peaks A, B, C, D, &amp; E. This number of peaks is arbitrary as more or less may be employed. 
       FIG. 9  shows the position of the four top wires A and four bottom wires B on the basket  700  from a front view. 
     The cleaning operation using the special serpentine or wave shaped support wires aids in the thorough cleaning of parts especially those requiring Fluorescent Penetrant Inspection, such as medical prostheses and so on. 
     It is understood that the only support for the part  612  are the support wires  611 . It has been ascertained that by bending the support wires in a serpentine or wave-like configuration, the part bounces or moves from the support wire contact points  611  to expose the contact areas of the part to the spray stream. The wire supports need not be spring-like as, for example, a guitar string or bed spring but are flexible and therefore can move or oscillate. They of course can be flexible or spring-like as well. In any event it is the function of the support wire to minimize the contact area with the part while allowing separation of the contact for a period sufficient to expose the contact area and therefore to enable cleaning of the same. 
     While the present invention has been described with reference to the illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to those skilled in the art on reference to this description. It is expressly intended that all combinations of those elements that perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Substitutions of elements from one described embodiment to another are also fully intended and contemplated.