JP4175473B2 - Abrasive material flow processing apparatus and method - Google Patents

Abstract

An apparatus and method for abrasive flow machining the orifice (18) of a workpiece (20) by using an abrasive media (15) whereby the apparatus (10) is capable of passing media (15) through the orifice (18) at a predetermined pressure and at a constant flow rate. In the alternative, the apparatus (10) is capable of passing media (15) through the orifice (18) at a fixed flow rate by using variable pressure upon the media (15) through the orifice (18).

Description

The present invention relates to processing by the flow of abrasive, more particularly, it relates to abrasive flow machining apparatus capable of machining a part of the orifice by carefully controlling the flow rate of the abrasive medium. The invention also relates to such a processing method.

Explanation of related technology

  Machining with an abrasive stream is a process in which a workpiece is polished or polished by moving a viscous medium containing abrasive particles under pressure through an orifice through or through the workpiece.

  Because conventional abrasive flow processing processes are designed to maintain a constant media extrusion pressure, the temperature, flow rate, and viscosity of the media often change significantly, which is the process of the abrasive flow processing equipment (AFM). This will adversely affect the system's ability to accurately predict time and therefore the overall outcome of the process.

  As an example, the temperature of the medium increases as the medium flow rate through the orifice increases. When the orifice receives a constant pressure medium flow, the flow rate of the medium through the orifice increases as the orifice wall becomes smoother and the orifice diameter increases. As a result, not only does the medium temperature increase, but such temperature increase is localized to the medium passing through the orifice at a high flow rate. For this reason, the temperature becomes very high, and a non-uniform temperature distribution is generated over the entire medium. If the medium temperature is high and the temperature varies throughout the medium, the medium cannot be processed in a consistent and effective manner. Accordingly, there is a need for an apparatus and method that effectively utilizes the media while maintaining the media temperature in a relatively narrow range.

  U.S. Pat. No. 3,634,973, assigned to the assignee of the present invention, discloses a reciprocating machining apparatus that uses media as an abrasive but operates in a manner that does not directly control the flow of media through the orifice. is doing. While this apparatus can effectively perform abrasive flow machining, controlling the flow rate will improve machining quality and extend the life of the media.

Summary of the Invention

The first embodiment of the present invention is directed to an abrasive flow device that moves the abrasive media through the workpiece orifice, which holds the workpiece fixed and holds one side. A workpiece holder having an upstream side and the other side as a downstream side is provided. There is a first positive displacement pump on the upstream side, connected to the upstream side of the holder, and forcibly moves the medium under a predetermined pressure to the downstream side of the holder. A medium resistance means is provided on the downstream side, and is connected to the downstream side of the holder to resist the medium flow to the downstream side, thereby maintaining the medium flow rate from the upstream side to the downstream side of the holder at a predetermined constant value. To be controlled.

In a second embodiment of the present invention, an abrasive flow device for moving an abrasive medium through an orifice of a workpiece includes a workpiece having one side as a first side and the other side as a second side. It has a workpiece holder that holds and holds it. There is a first positive displacement pump on the first side connected to the first side of the holder, and a second positive displacement pump on the second side connected to the second side of the holder Has been. In the first mode, the first positive displacement pump forcibly moves the media from the first side of the holder to the second side and the second positive displacement pump resists the flow of the second of the holder. controlling the flow rate of the side so as to maintain a predetermined constant value. In the second mode, the second positive displacement pump forces the media from the second side of the holder to the first side and the first positive displacement pump resists the flow so that the first of the holder controlled to be maintained the flow amount to the side at a predetermined constant value.

A third embodiment of the present invention is a method for performing abrasive flow machining with an abrasive medium through an orifice defining an upstream side and a downstream side of a workpiece. In this method, the medium is moved from the upstream side to the downstream side through the orifice at a predetermined constant pressure applied to the first side, and the medium is transferred to the downstream side while maintaining the predetermined constant pressure applied to the second side. It comprises the step of controlling the flow rate of the medium passing through the orifice to be maintained at a predetermined constant value by selectively restricting the flow.

A fourth embodiment of the present invention is a method for performing abrasive flow machining with an abrasive medium through an orifice defining a first side and a second side of a workpiece. In this method, the medium is moved from the first side to the second side through the orifice at a predetermined constant pressure applied to the first side, and the medium is transferred to the second side while maintaining the predetermined constant pressure. By selectively restricting the flow, the flow rate of the medium passing through the orifice is controlled to be maintained at a predetermined constant value, and the medium is moved from the second side to the first side through the orifice at a predetermined constant pressure. And controlling the flow rate of the medium passing through the orifice to be maintained at a predetermined constant value by selectively reducing the flow of the medium toward the first side while maintaining the predetermined constant pressure. .

A fifth embodiment of the present invention is a method for performing abrasive flow machining with an abrasive medium through an orifice defining an upstream side and a downstream side of a workpiece. In this method, the medium is moved from the upstream side to the downstream side through the orifice at a certain pressure, and the pressure is adjusted so that the flow rate of the medium passing through the orifice is controlled to be maintained at a predetermined constant value. Become.

  A sixth embodiment of the present invention is a method for performing an abrasive flow machining with an abrasive medium through an orifice defining a first side and a second side of a workpiece. This method moves the medium from the first side to the second side through the orifice by applying pressure to the first side and releasing the pressure on the second side, thereby reducing the pressure on the first side. Adjust the flow rate of the medium through the orifice from the first side to be constant, apply pressure to the second side, and release the pressure on the first side to remove the medium from the second side through the orifice. Moving to the first side and adjusting the pressure on the second side to keep the flow rate of the medium passing through the orifice from the second side constant.

  In one embodiment of the invention, the abrasive media is forced through the workpiece orifice under a constant pressure. The flow rate described in this example is equal to or less than the maximum flow rate when the downstream side of the orifice is opened to the atmosphere. In particular, a flow rate smaller than this maximum is obtained by limiting the media flow downstream of the orifice.

  Referring to FIG. 1, the figure shows a simplified abrasive flow apparatus 10 that moves an abrasive medium 15 through an orifice 18 of a workpiece 20. For purposes of explanation, the medium will be described as having a viscosity in the range of 1 and 50 million centipoise. An example of a medium having a relatively high viscosity is a viscoelastic plastic medium such as a semi-solid polymer composition. An example of a low-viscosity medium is a liquid abrasive slurry in which the abrasive is suspended or slurried in a fluid medium such as cutting fluid or honing fluid. This fluid may contain rheological additives and finely divided abrasive particles. A rheological additive produces a thixotropic slurry. The abrasive flow device 10 itself does not include a workpiece 20 having an orifice 18 and is provided with a workpiece holder 25 for holding the workpiece 20 fixedly, with one side 27 of the holder 25 being upstream or first. And the other side 29 defines the downstream or second side.

  The first positive displacement pump 35 on the upstream side 27 is connected to the upstream side 27 of the holder 25 and forcibly moves the medium 15 having a predetermined pressure to the downstream side 29 of the holder 25 through the orifice 18 of the workpiece 20.

  Since the free flow of the medium through the orifice 18 is blocked by the medium resistance means that resists the flow of the medium 15 to the downstream side 29 provided on the downstream side 29 of the holder 25, the upstream side 27 to the downstream side of the holder 25. The medium flow rate to 29 is controlled.

  As shown in FIG. 1, the first positive displacement pump 35 includes a cylinder 39 and a piston 37 inside the cylinder 39, and the piston 37 presses the medium 15 from the cylinder 39 to the downstream side 29 of the holder 25. The piston 37 is moved by the drive device 41. As described below, the drive 41 of the piston 37 is a hydraulic actuator (FIG. 4) or engages a gear 44 on a piston rod 38 extending from the piston 37, for example, as shown in FIG. A linear motor type actuator 42 using a worm gear 43 may be used. Although only two types of drives have been described, it will be appreciated that any number of drives known to those skilled in the art of hydraulic machines can be used in positive displacement pumps in accordance with the present invention.

  Referring to FIG. 1, one method of controlling both the pressure of the medium 15 and the flow rate of the medium 15 is to limit the amount of medium that can move to the downstream side 29 of the holder 25 to reduce the flow rate through the orifice 18. That is. More specifically, this can be realized by using the second positive displacement pump 55 as the medium resistance means 45. The second positive displacement pump 55 includes a cylinder 59 and a piston 57 inside thereof. The piston 57 can be operated to resist the flow of the medium to the downstream side 29 of the holder 25 and to control its flow rate.

  Other mechanisms can be used as the medium resistance means 45. Referring to FIG. 2, the configuration shown in FIG. 2 is similar to that of FIG. 1, but this medium resistance means 45 utilizes a relief valve 60. The medium 15 flows directly through the relief valve 60, and the release pressure of the relief valve 60 is controlled based on the desired flow rate of the medium.

  In the preferred embodiment, the relief valve 60 is a proportional electric relief valve (PER). The controller monitors the flow rate and reduces the voltage output to the proportional electric relief valve 60 when the actual flow rate is greater than the target flow rate. As a result, the flow rate of the medium 15 passing through the relief valve 60 decreases. Alternatively, when the actual flow rate is less than the target flow rate, the voltage output to this valve is increased to increase the amount of medium 15 that passes through. Other relief valves described herein can operate in a similar manner.

  In order to accurately measure the medium flow rate, a medium flow rate measuring device 65 is used. One such device is shown in FIG. When the first positive displacement pump 35 includes a cylinder 39 and a piston 37 therein, the piston 37 has a piston rod 38. By measuring the linear motion of the piston rod 38 using the encoder 66 as the flow measuring device 65, the medium flow rate can be determined. If the volume of the cylinder 39 and the moving speed of the piston 37 given by the encoder 66 are known, the medium flow rate can be obtained from the volume flow rate of the medium 15 through the orifice 18, and the controller can determine the medium resistance means 45 and the orifice. The flow rate of the medium 15 through 18 can be adjusted to increase or decrease.

  When the medium resistance means 45 is constituted by the second positive displacement pump 55 comprising the cylinder 59 and the piston 57 therein, as described above, the piston 57 has the piston rod 58, and under such circumstances, the medium flow The measuring device 65 is an encoder 67 that measures the linear motion of the piston rod 58 to determine the medium flow rate. Therefore, it is clear that the medium flow rate measurement is performed on either the upstream side 27 or the downstream side 29 of the holder 25.

  Each of the encoders 66, 67 may be a linear encoder or a rotary encoder, both of which are well known to those skilled in the art of measuring equipment.

  In the description so far, the flow of the medium 15 is limited to a unidirectional flow from the upstream side 27 to the downstream side 29 of the holder 25. In the embodiment of the abrasive flow device 10 shown in FIG. 2, this is just one way that the media 15 flows through the orifice 18 of the workpiece 20. However, as shown in FIG. 1, when the medium resistance means 45 is the second positive displacement pump 55, the role of the first positive displacement pump 35 and the second positive displacement pump 55 is the first operation mode. Then, the first positive displacement pump 35 forcibly moves the medium through the orifice 18, but the second positive displacement pump 55 acts as the medium resistance means 45 to control the flow rate of the medium 15, and the second operation In the mode, the second positive displacement pump 55 is forced to move the medium 15 toward the first positive displacement pump 35, but the first positive displacement pump 35 is used as a medium resistance means to control the flow in the opposite direction. It changes alternately. From this description, it will be seen that the media 15 reciprocates through the orifice 18 because these modes alternate.

  Referring again to FIG. 1, the first positive displacement pump 35 and the second positive displacement pump 55 include pistons 37 and 57 that are moved by driving devices 41 and 61, respectively. As before, each of the drive devices 41 and 61 may be the hydraulic actuator described above, or may be a linear motor type actuator shown in FIG. 3 as another device.

  When the abrasive flow device 10 is operating to move the media 15 in a single direction through the orifice 18 of the workpiece 21, the media 15 is orificed from the upstream side 27 to the downstream side 29 at a predetermined constant pressure. Move 15 Thereafter, the flow rate of the medium 15 passing through the orifice 18 is controlled by selectively restricting the flow of the medium 15 toward the downstream side 29 while maintaining a predetermined constant pressure.

  In another embodiment in which the abrasive flow device 10 is used in a reciprocating mode, the medium 15 has a predetermined constant pressure from an upstream side 27, referred to herein as a first side 27, to a downstream side 29, referred to as a second side 29. To move the orifice 18. The flow rate of the medium 15 passing through the orifice 18 is controlled by selectively restricting the flow of the medium 15 to the second side 29 while maintaining a predetermined constant pressure. Thereafter, the medium 15 is moved from the second side 29 to the first side 27 through the orifice 18 at a predetermined constant pressure. However, the flow rate of the medium 15 passing through the orifice 18 is controlled by selectively restricting the flow of the medium 15 to the first side 27 while maintaining a predetermined constant pressure. As before, the amount to selectively throttle the media flow is determined by the media flow rate through the orifice 18, which is determined by monitoring the flow rate using one or both of the linear encoders 66, 67. Is done.

  FIG. 4 is a more comprehensive schematic view of the abrasive flow apparatus 10 in which each positive displacement pump 35, 55 is provided with a drive 41, 61, which may be a hydraulic actuator.

  Specifically, FIG. 4 shows many of the components described above, and the reference numbers for these components are the same. However, the details of the drive devices 41 and 61 will be further described in connection with the operation of the abrasive material flow device 10.

  In a single stroke mode, where the first positive displacement pump 35 moves the medium 15 through the orifice 18 of the workpiece 20 to the medium resistance means 45, which is the second positive displacement pump 55, the drive 41 moves the medium through the orifice. On the other hand, the drive device 61 serves as a medium resistance means 45 for resisting the medium flow and controlling the flow. With reference to the hydraulic actuator 70 associated with the drive 41, the hydraulic pump 72 moves the medium through the supply line 74, but the hydraulic fluid 76 may be a solenoid operated poppet valve (SOP) on its way. Encounter valve 78. For illustrative purposes, this valve is a valve that allows a flow rate of 100% or zero. The hydraulic fluid 76 also encounters a proportional electric relief valve 80 that can adjust its resistance to flow as described above. When the hydraulic actuator 70 is used as the drive device 41, the poppet valve 78 is in the fully open position and the relief valve 80 is in the fully closed position. Accordingly, the hydraulic cylinder 82 is pressurized by the hydraulic fluid 76 at a pressure that the pump 72 can provide. This is a predetermined pressure that maintains a constant value throughout the stroke of the first positive displacement pump 35. Because the piston 82 in the hydraulic cylinder 82 is acted upon by the pressurized hydraulic fluid 76, the piston 37 is advanced relative to the medium 15 by the common piston rod 38, causing the medium 15 to move through the orifice 18 of the workpiece 20. Force move through.

  When the first positive displacement pump 35 and the hydraulic actuator 70 serve as the driving device 41, the second positive displacement pump 55 and the hydraulic actuator 90 serve as the medium resistance means 35. Specifically, the hydraulic actuator 90 comprises the same components as the hydraulic actuator 70 and includes a hydraulic pump 92, a supply line 94 and a hydraulic fluid 96. The hydraulic fluid is sent to poppet valve 98 and relief valve 100. The hydraulic actuator 90 further includes a hydraulic cylinder 102 having a piston 104, and the piston is connected to the piston rod 58 of the positive displacement pump 55. When the drive device 41 presses the medium 15 through the orifice 18, the medium 15 is pressed against the piston 57, so that a force acting on the hydraulic fluid 96 in the hydraulic actuator 90 is applied to the piston 104. When the second positive displacement pump 55 acts as the media resistance means 45, the hydraulic fluid 96 must pass through the relief valve 100 because the poppet valve 98 is fully closed.

  It should be noted in FIG. 4 that a single pump utilizing directional valves and hydraulic fluid storage means can be used in place of the two pumps 72,92.

  The flow rate of the medium through the orifice 18 is measured by one of the encoders 66 and 67 and sent to the controller. By comparing the flow rate of the medium with the target flow rate of the medium and adjusting the voltage of the proportional interlock relief valve 100, the hydraulic fluid 96 can pass through the relief valve 100, and the pull-in amount of the piston 104 is controlled. Control the flow rate of the medium. As described above, when the first positive displacement pump 35 serves as the drive device 41, the poppet valve 78 linked to the hydraulic actuator 70 is in the fully open position, and the relief valve 80 is bypassed. With respect to the hydraulic actuator 90 of the second positive displacement pump 55, since the poppet valve 98 is in the fully closed position, the hydraulic fluid 96 is forcibly moved through the relief valve 100, so that the flow of the hydraulic fluid is reduced. Thus, the flow rate of the medium is controlled.

  In the second mode, the configuration is the same but vice versa. More specifically, when the second positive displacement pump 55 acts as the drive device 61, the first positive displacement pump 35 acts as a medium resistance means. More specifically, in this configuration, since the poppet valve 98 is in a fully opened state, the total pressure applied to the hydraulic fluid 96 by the pump 92 is transmitted to the piston 104, which acts on the piston 57 via the piston rod 58. The medium 15 is forced to move toward the first positive displacement pump 35 through the orifice 18. The hydraulic actuator 70 acting as a medium resistance means is configured to forcibly move the hydraulic fluid 76 through the relief valve 80 when the poppet valve 78 is fully closed. The release pressure of the relief valve 80 is electronically controlled by the controller based on the medium flow rate measured by one of the encoders 66 and 67. Thus, the operation of the abrasive flow apparatus alternates between the first mode and the second mode, so that the medium 15 is reciprocated through the orifice 18 of the workpiece 20.

  FIG. 5 is a schematic diagram of the hardware used in at least one embodiment of the present invention. The same reference numbers are used as before. However, some additional components are also illustrated. More specifically, a pressure sensor 105 comprising a pressure transducer associated with the hydraulic pressure supply line 74 measures the pressure in that line. In addition, a pressure sensor 108 associated with the supply line 94 measures the pressure in that line. It will be appreciated that the pressure in supply lines 74 and 94 is transmitted to medium 15 by pistons 37 and 57, respectively. Further, the temperature of the medium 15 is measured by the temperature sensor 110.

  The pressure of the hydraulic fluid converted to the pressure of the medium 15 is processed by the controller 112 along with the linear position of each piston 37, 57, which is a pressure relief valve 80 for a positive displacement pump that acts as a medium resistance means. Works to change the release pressure.

  By controlling the flow rate of the medium 15 through the orifice 18 more precisely, the temperature can be kept in a narrow temperature range as compared with the case without the flow rate control. Nevertheless, it is still desirable to remove heat from the media 15 during the abrasive flow machining process. For this reason, a cooling collar 115 associated with the cylinder 39 of the first positive displacement pump and a cooling collar 117 associated with the cylinder 59 of the second positive displacement pump are provided. Each of these cooling collars 115, 117 has a plurality of cooling tubes 116, 118 that can transfer heat from the medium 15 as needed. Under certain circumstances, these cooling collars 115, 117 can be used to heat the media 15, such as when the media 15 must begin the abrasive process at the lowest temperature. The cooling collars 115 and 117 are arranged outside so as not to obstruct the flow of the medium 15. However, their effectiveness is limited because the transfer of heat from the medium 15 to the collars 115, 117 is due to conduction through the walls of the cylinders 39, 59.

  An in-line heat exchanger can be introduced directly into the flow path of the medium 15. FIG. 7 shows an example of such a heat exchanger 200 in which hollow cooling fins 202 are provided in an internal passage 205 through which the medium 15 flows. The coolant passes through the coolant inlet 207 and flows into the hollow fins 202 and exits from the coolant outlet (not shown). Bolts are passed through the circumferential holes 209 of the collar 210 to fix the heat exchanger 200. The heat exchanger 200 is secured to one or both of the cylinders 39 adjacent to the holder 25. This heat exchanger 200 has a large heat exchange rate with the medium 15, but partially impedes the flow of the medium 15, so it may be necessary to increase the size of the cylinder to ensure a given flow rate. .

  The controller 112 (FIG. 5) may be a programmable logic controller such as the model Micrologic 1200 commercially available from Allen Bradley Company. Further, the proportional electric relief valve may be type TS 10-26, commercially available from Hydro Force, Inc. Further, the poppet valve may be a two-way normally open valve SV 10-23 commercially available from Hydro Force, Inc.

  The signals from the encoders 66 and 67 are used by the controller 112 to calculate the actual flow velocity of the medium 15. A suitable encoder is the orthogonal type commercially available from Automation Direct, Inc. Encoders 66, 67 and poppet valves 78, 98 and relief valves 80, 110 allow controller 112 to maintain the media flow rate at a desired consistent value. This consistent value of flow allows the media to remain in a narrow temperature range as measured by the temperature sensor 110, thereby maintaining the media viscosity at a consistent value. When the viscosity of the medium is essentially constant, the controller 112 can more accurately predict the processing time at which the desired degree of processing of the orifice 18 is obtained.

  What has been described above is that the drive devices 41, 61 alternately press the medium 15 at a constant pressure through the orifice 18 of the workpiece 20, and at the same time the flow rate of the medium 15 may be a pressure relief valve or other drive device. It was to be controlled by the retraction or resistance of the resistance means 51.

  Even if the medium resistance means 45 is eliminated, it is still possible to maintain a constant flow rate of the medium. This is done by changing the pressure applied to the medium 15 by the drive device 41. As the abrasive flow machining process proceeds, the media 15 flow rate through the orifice 18 tends to increase if the media is under constant pressure. Therefore, in order to maintain the medium flow rate at the same value, it is necessary to reduce the pressure applied to the medium 15 by the driving device 41. This can be done in a single direction or by reciprocation as before.

  Referring to FIG. 6, the medium 15 is moved from the upstream side 27 through the orifice 18 to the downstream side 29 at a specific pressure in a single direction. The flow rate is monitored using the encoder 66 and the pressure applied to the medium is adjusted so that the flow rate of the medium 15 passing through the orifice 18 is constant. Specifically, the encoder 66 measures the flow rate by monitoring the linear motion of the piston rod 38 associated with the piston 37. The pump 72 carries the pressurized hydraulic fluid to the hydraulic cylinder 82 where it acts on the hydraulic piston 84. In the configuration shown in FIG. 4, the downstream side 29 of the holder 25 can be released into the atmosphere as shown in FIG. Alternatively, and referring again to FIG. 4, the flow of media 15 applied under pressure to the first side 27 through the orifice 18 is not obstructed or assisted by the piston 57, but the pressure on the second side 29. It is possible to coordinate the movements of the piston 37 and the piston 57 so that is released. With this configuration, the abrasive flow apparatus 10 shown in FIG. 5 is configured such that, in the first mode, the second positive displacement pump 55 is passive while the first positive displacement pump 35 forcibly moves the medium 15 through the orifice 18. Mode, and in the second mode, the first positive displacement pump 35 can operate in a reciprocating motion mode, which is a passive mode, while the second positive displacement pump 55 forcibly moves the medium 15 through the orifice 18. it can.

When the medium resistance means 45 is constituted by the second positive displacement pump 55 comprising the cylinder 59 and the piston 57 therein, as described above, the piston 57 has the piston rod 58, and under such circumstances, the medium flow The quantity measuring device 65 is an encoder 67 that measures the linear motion of the piston rod 58 to determine the medium flow rate. Therefore, it is clear that the medium flow rate measurement is performed on either the upstream side 27 or the downstream side 29 of the holder 25.

FIG. 3 is a schematic diagram showing two opposing positive displacement pumps that push abrasive media through an orifice of a workpiece. FIG. 2 is a schematic of a single positive displacement pump that displaces the media through the workpiece orifice and then resists media flow. Fig. 5 shows an opposing positive displacement pump in which the drive is a linear actuator and moves the medium back and forth through an orifice. FIG. 2 is a schematic diagram of two opposing positive displacement pumps and a control system that operates them. FIG. 2 is a schematic diagram of an actuation system showing two opposing positive displacement pumps and associated hardware. 1 is a schematic diagram of a single positive displacement pump that moves media through an orifice and releases it to an open environment. FIG. It is a perspective view of the in-line heat exchanger which can be used for temperature control of a medium.

Claims (40)

An abrasive flow device for moving an abrasive medium through an orifice in a workpiece,
a) a workpiece holder for securing and holding a workpiece, wherein one side is upstream and the other side is downstream;
b) a first positive displacement pump which is upstream and connected to the upstream side of the holder and forcibly moves the medium to the downstream side of the holder at a predetermined pressure;
c) medium resistance means which is downstream and connected to the downstream side of the holder and resists the flow of fluid downstream;
d) a medium flow rate measuring device for measuring the flow rate of the medium passing through the holder;
controller e) first volumetric pump while maintaining a predetermined pressure in the upstream side, the flow rate of the medium from the upstream side to the downstream side of the holder to control the medium resistance means so that is maintained at a predetermined constant value Abrasive material flow equipment consisting of The abrasive of claim 1, wherein the first positive displacement pump comprises a cylinder and a piston therein, the piston being operable to push the medium from the cylinder downstream of the hole, the piston being moved by a drive. Flow device. The abrasive material flow device of claim 2 wherein the drive is a hydraulic actuator. The abrasive material flow device according to claim 2, wherein the driving device is a linear motor type actuator. 2. The abrasive flow apparatus of claim 1 wherein the media resistance means is a relief valve. 6. The abrasive material flow apparatus according to claim 5, wherein the medium resistance means is a proportional electric relief valve. The abrasive flow apparatus of claim 1, wherein the media resistance means is a second positive displacement pump. 8. The abrasive flow of claim 7, wherein the second positive displacement pump comprises a cylinder and a piston therein, the piston being operable to resist and control the flow of media downstream of the holder. apparatus. 2. The abrasive flow apparatus of claim 1, wherein the first positive displacement pump comprises a cylinder and a piston therein, the piston having a piston rod, and an encoder measures the linear flow of the piston rod to measure the flow rate of the medium. . The medium resistance means is a second positive displacement pump comprising a cylinder and a piston inside the piston. The piston has a piston rod, and the medium flow rate measuring device measures the linear motion of the piston rod to determine the flow rate of the medium. The abrasive material flow device of claim 1. The abrasive material flow apparatus of claim 1, further comprising a medium cooling means. 12. The abrasive flow apparatus of claim 11, wherein the cooling means comprises a cooling cover around at least one of the first positive displacement pump cylinder and the second positive displacement pump cylinder. 12. The abrasive flow apparatus of claim 11 wherein the cooling means comprises an in-line heat exchanger adjacent to the holder in at least one of the first positive displacement pump cylinder and the second positive displacement pump cylinder. An abrasive flow device for moving an abrasive medium through an orifice in a workpiece,
a) a workpiece holder for securing and holding a workpiece, wherein one side is a first side and the other side is a second side;
b) a first positive displacement pump on the first side, connected to the first side of the holder and forcibly moving the medium to the second side of the holder at a predetermined pressure;
c) comprising a second positive displacement pump on the second side and connected to the second side of the holder;
d) In the first mode, the first positive displacement pump forces the medium from the first side of the holder to the second side and the second positive displacement pump resists the flow of the holder, Control the flow to the second side,
e) In the second mode, the second positive displacement pump forcibly moves the medium from the second side of the holder to the first side and the first positive displacement pump resists the flow so that the first of the holder Control the flow to the side of 1,
f) a medium flow rate measuring device for measuring the flow rate of the medium passing through the holder;
abrasive g) medium further comprising a controller for controlling the first positive displacement pump and the second positive displacement pump so that maintained the flow rate of the medium at a predetermined constant value when reciprocated through the holder Flow device. 15. The abrasive material flow device of claim 14, wherein each of the first and second positive displacement pumps comprises a cylinder and a piston therein, the piston being moved by a drive device. The abrasive flow apparatus of claim 15, wherein the at least one drive is a hydraulic actuator. The abrasive material flow device of claim 15, wherein the at least one drive is a linear motor type actuator. The first positive displacement pump and the second positive displacement pump each have a piston rod associated with the piston, and the media flow rate measuring device is an encoder that determines the linear motion of at least one piston rod to measure the media flow rate. The abrasive material flow device of claim 14. The abrasive flow apparatus of claim 14, further comprising a medium cooling means. 20. The abrasive flow device of claim 19, wherein the cooling means comprises a cooling cover around at least one of the first positive displacement pump cylinder and the second positive displacement pump cylinder. 20. The abrasive flow apparatus of claim 19, wherein the cooling means comprises an in-line heat exchanger adjacent to the holder in at least one of the first positive displacement pump cylinder and the second positive displacement pump cylinder. A method of performing abrasive flow machining with an abrasive medium through an orifice defining an upstream side and a downstream side of a workpiece,
a) The medium is moved from the upstream side to the downstream side through the orifice at a predetermined constant pressure applied to the upstream side,
b) Monitor the flow rate,
from step flow of medium passing through the orifice by narrowing the flow of the medium to the downstream side in the selective while maintaining a predetermined constant pressure on the c) upstream is controlled to be maintained at a predetermined constant value A processing method using an abrasive material flow. The medium is forced through the orifice by a first positive displacement pump having a piston with a piston rod, the piston is moved in a cylinder by a drive connected to the piston, and the step of monitoring the flow rate is the piston rod. 23. The method of claim 22, wherein the method is performed by monitoring linear motion. 23. The method of claim 22, further comprising the step of controlling the flow rate of the medium by restricting the downstream flow of the medium. 25. The method of claim 24, wherein the step of restricting the flow is performed using a proportional motorized relief valve that resists downstream flow of the media. 25. The method of claim 24, wherein the step of restricting the flow is performed using a second positive displacement pump that resists downstream flow of the media. 23. The method of claim 22, further comprising the step of cooling the medium. A method of performing abrasive flow machining with an abrasive medium through an orifice defining a first side and a second side of a workpiece, comprising:
a) moving the medium from the first side to the second side through the orifice at a predetermined constant pressure on the first side;
b) monitoring the flow rate through the orifice,
c) so that the flow rate of a medium passing through the orifice is maintained at a predetermined constant value by throttling the flow of media to the second side to the selective while maintaining a predetermined constant pressure on the first side of Control
d) moving the medium from the second side to the first side through the orifice at a predetermined constant pressure on the second side;
e) so that the flow rate of a medium passing through the orifice by narrowing the flow of the medium to the first side while maintaining a predetermined constant pressure on the second side of the selective is maintained at a predetermined constant value A method comprising a controlling step. The medium is forced through an orifice by a first positive displacement pump with a cylinder and a piston inside it, the piston has a piston rod, and the step of monitoring the flow is performed by monitoring the linear motion of the piston rod. 30. The method of claim 28. 29. The method of claim 28, wherein the step of restricting the flow is performed using a proportional electric relief valve that resists media flow from the first side to the second side. 29. The method of claim 28, wherein the step of restricting the flow is performed using a second positive displacement pump that resists media flow from the first side to the second side. 30. The method of claim 28, further comprising the step of cooling the medium. A method of performing abrasive flow machining with an abrasive medium through an orifice defining an upstream side and a downstream side of a workpiece,
a) moving the medium at a certain pressure from upstream to downstream through the orifice;
b) monitoring the flow rate through the orifice,
How the flow rate of medium passing through the orifice is made of steps of to be maintained at a predetermined constant value by adjusting the pressure on the c) upstream. 34. The method of claim 33, further comprising monitoring the flow rate. The medium is forced through the orifice by a first positive displacement pump having a piston with a piston rod, the piston is moved in a cylinder by a drive connected to the piston, and the step of monitoring the flow rate is the piston rod. 35. The method of claim 34, wherein the method is performed by monitoring linear motion. 34. The method of claim 33, further comprising the step of cooling the medium. A method of performing abrasive flow machining with an abrasive medium through an orifice defining a first side and a second side of a workpiece, comprising:
a) moving the medium from the first side to the second side through the orifice by applying pressure to the first side and releasing the pressure on the second side;
b) monitoring the flow rate through the orifice,
c) as the flow rate of the medium passing through the orifice from the first side by adjusting the pressure in the first side is kept at a predetermined constant value,
d) moving the medium from the second side to the first side through the orifice by applying pressure to the second side and releasing the pressure on the first side;
e) a method of the flow rate of medium passing through the orifice from the second side to adjust the pressure of the second side is comprised of steps that is maintained at a predetermined constant value. The medium is forced through an orifice by a first positive displacement pump with a cylinder and a piston inside it, the piston has a piston rod, and the step of monitoring the flow is performed by monitoring the linear motion of the piston rod. 38. The method of claim 37. 38. The method of claim 37, wherein the step of reducing the flow is performed using a second positive displacement pump to resist media flow from the first side to the second side. 38. The method of claim 37, further comprising cooling the medium.

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