Abstract:
An end face polishing machine has a jig plate for supporting at least one workpiece. A polishing plate is mounted to undergo rotation and revolving movement. A polishing sheet is disposed over the polishing plate for rotation and revolving movement therewith. An elastic member having a hardness that varies with temperature is disposed between the polishing sheet and the polishing plate. A pressing unit presses the end face of the workpiece against a surface of the polishing sheet during rotation and revolving movement of the polishing plate to thereby polish the end face of the workpiece during a polishing operation. A temperature control unit controls the temperature of the elastic member during the polishing operation to thereby polish the end face of the workpiece into a spherical surface during the polishing operation.

Description:
BACKGROUND OF THE INVENTION 
     FIELD OF THE INVENTION 
     The present invention relates to an end face polishing machine and to a method of polishing a rod-shaped member. 
     For end face polishing machines traditionally used for polishing the end face of ferrules, a machine has been known in which a polishing jig fixed with ferrules is disposed on a rotary and revolutionary polishing plate for polishing. In addition, ferrule polishing has been conducted according to a plurality of steps having different process conditions from a rough surface state to a final finish state. 
     However, the traditional polishing machine has conducted input control for polishing and polishing conditions by a single machine. Thus, it has been difficult to change the polishing conditions varied from each of a plurality of ferrules and the conditions for each of polishing steps, to adjust conditions according to changes in the number of ferrules and to input data, because of the size of the overall machine and the configuration of indication and input. 
     Therefore, skilled workers have to manipulate operations of the polishing machine, thereby hindering the production of a wide variety of products. 
     Traditionally, the correction operation for the polishing conditions takes effort and time because a user stops and manipulates the machine at each event. Errors in correction tend to occur, and yields in products are reduced as well. There have been problems that the user has to stay the position to know the number of products, the kinds of ferrules and the operation status of the polishing machine, and that investigations for causes are not simple when defects are generated in products because correction conditions are not recorded. 
     In view of the foregoing drawbacks in the conventional art, it is an object of the invention to provide an end face polishing system of ferrules capable of configuring a system for polishing a plurality of various types of ferrules under a plurality of process conditions, shortening input time for the process conditions of polishing steps, storing the process conditions, and structuring a LAN system allowing a plurality of machines to remotely operated. 
     SUMMARY OF THE INVENTION 
     According to the present invention, a polishing system has a polishing machine and a computer. The polishing machine includes a polishing plate, a pressing part for pressing the end face of a rod-shaped member onto a polishing sheet disposed over the polishing plate, and a pressing force control part for controlling the pressure of the pressing part, and the computer is connected to the polishing machine with a communication line for transmitting pressing force information to the pressing force control part. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a diagram illustrating a polishing system of the invention; 
     FIG. 2 is a diagram illustrating the polishing system of the invention; 
     FIG. 3 is a block diagram illustrating a pressing force control part of the invention; 
     FIG. 4 is a diagram illustrating the top face of a jig plate of the invention; and 
     FIG. 5 is a diagram illustrating a display part of a control machine in the polishing system of the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the invention, an end face polishing machine has been configured as a first embodiment, the end face polishing machine includes: 
     a jig for supporting at least one rod-shaped member; 
     a polishing plate performing rotary and revolutionary movement; 
     a polishing sheet disposed over the polishing plate for polishing the end face of the rod-shaped member; 
     a pressing part for pressing the end face of the rod-shaped member onto the polishing member, 
     a pressing force control part for controlling a pressure of the pressing part, and 
     a pressing force information input part for inputting a pressing force set value to the pressing force control part through a communication line. 
     Furthermore, as a second embodiment, the first embodiment can be added with a pressure detecting part for detecting the pressure in pressing, and a pressing force information output part for outputting pressure information of the pressure detecting part through the communication line. 
     As a third embodiment, it is the end face polishing machine in which the pressing force set value is a pressure in pressing and pressing time in the first or second embodiment. 
     As a fourth embodiment, it is a ferrule polishing control machine including: 
     a ferrule type input part for selecting one ferrule from a plurality of ferrule types stored in a computer beforehand; 
     an end face shape input part for selecting one end face shape from a plurality of ferrule end face shapes stored in the computer beforehand; 
     a connector type input part for selecting one connector from a plurality of connector types stored in the computer beforehand; 
     a polishing number input part for selecting the number of ferrules to be mounted on a polishing jig from numbers stored in the computer beforehand; and 
     a transmitting part for selecting polishing pressure information stored in the computer according to polishing information inputted from the ferrule type input part, the end face shape input part, the connector type input part, and the polishing number input part, and for transmitting the polishing pressure information to a ferrule polishing machine. 
     As a fifth embodiment, a ferrule polishing method includes the steps of: 
     selecting one ferrule from a plurality of ferrule types stored in a computer beforehand; 
     selecting one end face shape from a plurality of ferrule end face shapes stored in the computer beforehand; 
     selecting one connector from a plurality of connector types stored in the computer beforehand; 
     selecting the number of ferrules to be mounted on a polishing jig from numbers stored in the computer beforehand; and 
     selecting polishing pressure information stored in the computer beforehand according to polishing information inputted from the unit adapted to input a ferrule type, the unit adapted to select an end face shape, the unit adapted to input a connector type, and the unit adapted to input a polishing number, and for performing ferrule end face polishing. 
     As a sixth embodiment, it is a ferrule polishing program including the steps of: 
     selecting one ferrule from a plurality of ferrule types stored in a computer beforehand; 
     selecting one end face shape from a plurality of ferrule end face shapes stored in the computer beforehand; 
     selecting one connector from a plurality of connector types stored in the computer beforehand; 
     selecting the number of ferrules to be mounted on a polishing jig from numbers stored in the computer beforehand; and 
     selecting polishing pressure information stored in the computer according to polishing information inputted from the unit adapted to input a ferrule type, the unit adapted to select an end face shape, the unit adapted to input a connector type, and the unit adapted to input a polishing number, and for performing ferrule end face polishing. 
     As a seventh embodiment of the invention, it is an end face polishing machine including: 
     a jig for supporting at least one rod-shaped member; 
     a polishing plate performing rotary and revolutionary movement; 
     a polishing sheet disposed over the polishing plate for polishing the end face of the rod-shaped member; 
     a pressing part for pressing the end face of the rod-shaped member onto the polishing member; 
     an elastic member between the polishing sheet and the polishing plate; and 
     a temperature control unit adapted to control the elastic member. 
     As an eighth embodiment, the temperature control unit is a heating unit in the seventh embodiment. 
     As a ninth embodiment, the temperature control unit is a cooling unit in the seventh embodiment. 
     Furthermore, the invention has a polishing system including a polishing machine and a computer, 
     the polishing machine including: 
     a polishing plate; 
     a pressing part for pressing the end face of a rod-shaped member onto a polishing sheet disposed over the polishing plate; and 
     a pressing force control part for controlling a pressure of the pressing part, and 
     the computer connected to the polishing machine with a communication line. 
     Moreover, in the foregoing polishing system, wherein the computer indicates set values and actual measurements for pressure in pressing controlled by the pressing force control part. 
     In the foregoing polishing system, the computer controls set values for pressure in pressing controlled by the pressing force control part. 
     In the foregoing polishing system, the computer has a unit adapted to input the number of the rod-shaped members and a unit adapted to indicate the number inputted. 
     In the foregoing polishing system, the computer has a unit adapted to input and indicate a connector type for disposing the rod-shaped member. 
     In the foregoing polishing system, the computer has a unit adapted to input and indicate a type indicating the shape of the rod-shaped member and a shape, and a unit adapted to indicate the type and the shape. 
     In the foregoing polishing system, the computer has a unit adapted to input and an end face shape of the rod-shaped member and a unit adapted to indicate it. 
     In the foregoing polishing system, the computer has a unit adapted to input and indicate a process condition for a plurality of polishing steps. 
     In the foregoing polishing system, the process condition is polishing time. 
     In the foregoing polishing system, the process condition is an indication to indicate a step being implemented among the plurality of polishing steps. 
     In the foregoing polishing system, the process condition is remaining time for the polishing step. 
     In the foregoing polishing system, the process condition is a pressure in pressing. 
     In the foregoing polishing system, the process condition is an actual measurement for pressure in pressing. 
     In the foregoing polishing system, the process condition is the rotation number of the polishing plate. 
     Another end face polishing machine comprises: 
     a polishing plate having a polishing sheet over the top face; and 
     a heating unit for heating the polishing sheet. 
     The end face polishing machine includes a polishing plate having a polishing sheet over the top face and a heating unit for heating the polishing sheet, and a method of controlling the hardness of the polishing sheet by the heating unit has been used. 
     Another polishing machine comprises: 
     a unit adapted to periodically change a pressure of pressing the end face of rod-shaped member onto a polishing sheet; and 
     a unit adapted to detect a difference between the pressure in pressing and the pressure applied. 
     In the foregoing polishing machine, the difference is a difference in magnitudes or pressure. It has been the polishing machine, wherein the difference is a phase difference of pressure. 
     Another polishing machine comprises: 
     a unit adapted to periodically change a recessed amount for pressing an end face of a rod-shaped member onto a polishing sheet in the thickness direction of the polishing sheet; and 
     a unit adapted to detect a difference between the recessed amount and the pressure applied. 
     Hereafter, embodiments of the invention will be described in accordance with the drawings in detail. FIG. 1 is a front view illustrating an end face polishing machine in one embodiment of the invention. FIG. 2 is a side view illustrating the end face polishing machine in one embodiment of the invention. FIG. 3 is a block diagram illustrating a pressing force control part of the end face polishing machine in one embodiment of the invention. FIG. 4 is a plan view illustrating the state that workpieces, such as ferrules, are fixed to a jig plate of the end face polishing machine in one embodiment of the invention. 
     In FIG. 1, over the top fae of a polishing plate  60  moved by one kind of a combination of rotation, revolution and oscillation, an elastically deformable polishing sheet  70  is placed, and an elastic member  71  is disposed between the polishing plate  60  and the polishing sheet  70 . The polishing plate  60 , polishing sheet  70 , and elastic member  71  define a polishing structure which undergo the combination of movements as set forth above during a polishing operation. Then, on the upper part of the polishing sheet  70 , a jig plate  50  for detachably fixing ferrules W to both ends is placed so as to contact the end face of the ferrules W to the surface of the polishing sheet  70 . Here, the jig plate  5  is connected to one end of a lever  10  and pressed downward, and the end face of the ferrules W is pressed onto the polishing sheet. 
     Subsequently, near the end part opposed to the end part of the lever  10  connected to the jig plate  50 , a lower spring  24  for pushing up the lever  10  from under is placed. Then, above the position facing to the lower spring  24  of the lever  10 , a pressure sensor  23  for detecting pressure applied to the jig plate  50  is placed. Here, a load cell is used as the pressure sensor. 
     The lower end part of a pressing head  21  is placed so as to contact the top face of the pressure sensor  23 . Above the pressing head  21 , an upper spring  22  for pressing the pressing head  21  is placed. 
     In the invention, the top face and the lower face of the lever  10  are pressed by the lower spring  24  and the upper spring  22 , respectively. Thus, the lower spring  24  allows the load of the lever  10  or the load combined with the lever  10  and the jig plate  50  to be cancelled to achieve zero balance. Consequently, the pressure sensor  23  can detect only the load applied from above the lever  10 . Accordingly, even when the types of the lever  10  or jig plate  50  and the types and number of ferrules W are changed, the polishing load can be detected accurately. 
     In the drawing, the lever  10 , the upper spring  22 , the pressing head  21 , the pressure sensor  23 , and the lower spring  24  are configured of a part of the pressing part  20 . 
     Here, under the polishing sheet  70 , the elastic member  71  made of a rubber sheet is disposed for use in forming a convex surface. Under the elastic member  71  or near the polishing plate  60 , a heater  61  such as silicon rubber heater or film heater is disposed, whereby the temperatures of the rubber sheet can be kept constant, and the hardness of the rubber sheet can be varied softer or harder, allowing changes in polishing condition, pressure conditions, and conditions for finishing and lapping. In addition, it is also possible to adjust changes in the elasticity of the rubber sheet over time to prolong the lifetime. The formation of the rubber sheet is a varied, whereby the end face shape of the rod-shaped member can be formed flat or formed to have convex surfaces, allowing flat polishing, APC polishing, and PC polishing. Furthermore, instead of the heater  61 , it is possible that a cooling device  62  formed of a cooling pipe having water or a cooling medium communicated inside thereof, or of a bismuth-tellurim based Peltier element is disposed to cool the rubber sheet and the hardness is varied. Other than this, it is also possible that an infrared heater or cooling pipe is disposed from above the jig plate  50  to control temperatures. Besides, both mechanisms for cooling and heating are disposed to control temperatures more accurately and in the wider temperature range, whereby the end face shape can be finished precisely. 
     Next, FIG. 2 shows the pressing part  20 . 
     The pressing part  20  has a mechanism for reciprocating the lever  10 . The lever  10  is connected to the pressing head  21  through the pressure sensor  23  for detecting pressure, and the pressing head  21  and the lever  10  are moved vertically by the rotation of a screw  26 , which servers to transmit the force to press the lever  10  to the jig plate  50 . 
     The lever  10  is provided with a guide  28  so as to accurately reciprocate vertically. For the guide  28 , a linear guide arranged in parallel to the axis of the upper spring  22  or lower spring  24  is used. Accordingly, detecting the pressure due to the transverse movement of the lever  10  can be eliminated to allow improving the SN ratio. 
     The screw  26  transmits the rotation of a motor  25  through a shaft  25   a , a pulley  27   a , a belt  29 , and a pulley  27   b  for rotation, and then it moves the lever  10  vertically. The pressure sensor  23  detects the load applied by the rotation of the motor  25 , and a pressing force control part  40  feeds electric power for driving the motor  25  to configure a pressing force control circuit. 
     FIG. 3 shows the pressing force control part  40 . The pressing force control part  40  includes an A/D converter  33  for converting the output of the pressure sensor  23 , a first storage device  34  for storing a control program, a second storage device  35  for storing set pressures, a CPU  37  for comparing and operating detected values and predetermined pressure values and for determining output data for driving the motor  25 , in which the output of the CPU  37  is converted by a D/A converter  36 , and the output is inputted to a driver  44 , and the electric power for driving the motor  25  is outputted. Here, the CPU  37  is connected to a serial interface  38 , and it interconnects a polishing control machine  39  and a server by protocols such as TCP/IP, wireless LAN, and bluetooth in the connection of an RS-232C, a USB, and a 100 base. Therefore, the polishing machine is downloaded with programs for polishing conditions or with polishing conditions, allowing delivery of the polishing conditions optimal for user conditions. 
     According to the invention, pressure applied to the end part of the ferrule can be controlled so as to be a predetermined set value. Consequently, the load applied to the ferrule end part can be kept constant in polishing. 
     Furthermore, in the initial polishing state of the ferrule, when the end part of an optical fiber is exposed from the ferrule end part, the load is reduced to have the optical fiber end face and the ferrule end face in a nearly equal plane. When cracks or chips are not generated in the optical fiber end part, the polishing load is increased to allow rapid polishing. Here, switching loads is also feasible by a method of specifying them by a timer inside the pressing force control part  40 , or a method of operating values of a real time clock. In addition, it is possible that the electric power of the motor  25  or the electric power of the motor for driving the polishing plate  60  is detected, and the drive load of the motor detects the start of polishing the ferrule end part, i.e. the state that the initial polishing of the optical fiber end part is finished to be in the same plane as the ferrule. 
     Moreover, as another method for detecting the polished state, the relationship between the feed of the screw  26  and changes in pressure can determine the contact state of the ferrule end part to the polishing sheet  70  according to the relationship between the drive of the motor  25  and the output of the pressure sensor  23 . This method can detect the point of matching the optical fiber end face with the ferrule end face and the generation of cracks or chips in the optical fiber. When pressure values equal to or above the specified values are detected, it is determined abnormal to stop operations of the polishing machine, and waste time due to polishing defectives can be reduced. 
     Besides, the pressure values for polishing loads to be set are reduced as the steps proceed, a greater value in rough finish to be reduced in middle finish and then in fine finish, allowing the improvement in polishing rates and preventing polishing scratches from being generated. 
     In addition to this, according to differences in the types and particle diameters of abrasives, and differences in the materials, end face shape and diameters of ferrules, pressure to be set can be varied, and the object optimal conditions can be selected. 
     Furthermore, pressure in pressing is slightly varied to apply shifts in the vertical direction of the ferrule by free decay vibration or forced vibration, or pressure variations are applied to give modulation in the vertical direction, whereby changes in elasticity, complex elastic modules, and dynamic elastic modules due to modulation frequencies and a magnitude of pressure changes or phase shifts allow monitoring the degraded states of the polishing sheet or changes in the polishing state. Moreover, the temperatures near the polishing sheet are kept constant by the heater, whereby polishing monitor based on changes in elastic modules can be performed from the relationship between a logarithm LOG (F) for a modulation frequency F and an inverse number  1 /(T) for a temperature absolute value T, allowing variations in the polishing states to be reduced, and yields to be controlled from remote locations. 
     FIG. 4 shows a diagram illustrating the jig plate  50  of the invention. Two ferrules W are clamped with a fixing block  51  against each side of a hexagon for fixing. 
     FIG. 5 is a diagram illustrating a display part in a control machine in the polishing system of the invention. At the lower left of a title  100 , a numbers indication part  200  for indicating the number of ferrules polished simultaneously has input buttons  201 ,  202 ,  203 ,  204 ,  205 ,  206  and  208  for inputting six to sixteen ferrules or the number other than these, and a pieces indication  210 . Here, the input button  201  has inputted six ferrules, and thus the pieces input button in  210  is indicated in red. A type indication part  300  for indicating connector types is under the numbers indication part  200 . Disposed are type indications for indicating Ferrule only, FC Connector, SC Connector, ST Connector, MU Connector, and LC Connector and other than these, and input buttons  301 ,  302 ,  303 ,  304 ,  305 ,  306  and  307  corresponding to each of them; Ferrule is selected to indicate the input button  301  in red. 
     Furthermore, a type indication part  400  for indicating ferrule shapes has type indications  410 ,  411 ,  412 ,  413 , and  414  for indicating φ 1.25, φ 2.0, φ 2.5 Flat, φ 2.5 Predome, and the others. When input buttons  401 ,  402 ,  403 ,  404  and  405  corresponding thereto are inputted, the selected button turns red. 
     In addition, a condition indication part  500  has condition indications for indicating FLAT Polishing, ANGLED FLAT Polishing, APC Polishing, PC Polishing, SPC Polishing, UPC Polishing, and UPC 55 dB Polishing, and input buttons  501 ,  502 ,  503 ,  504 ,  505 ,  506 ,  507  and  508  for selecting and indicating each condition. 
     Moreover, a process indication part  600  for indicating polishing processes displays a process table  601 . Disposed are process step indication parts  610 ,  611 ,  612 ,  613  and  614  for indicating a first polishing step to a fifth polishing step, and item indications for indicating process conditions for each of steps and parameters: a polishing time  620  for indicating process time for each step, an on process  621  for indicating the step now being implemented, a remaining polishing time  622  for indicating remaining time for each step, a programmed pressure  623  for setting a polishing pressure, an actual pressure measurement  624  for indicating measurements of pressure actually applied, and a rotation number  625  for indicating the rotation number of the polishing plate. 
     Besides, a condition input and indication part  650  indicates values for indicating the polishing conditions to be set and actual numeric values, also serving as an input screen. 
     In addition to these, there are an alarm  700  for signaling abnormal circumstances, an indication part for a massage  710 , an operation status  720  for indicating operation states, an on process indication  730  for indicating during polishing, a finish indication  740  for indicating the completion of polishing, a manual switch  750  for switching operation modes, an online control  760  for indicating an online state, and a select indication  770  for indicating selections. 
     There area start button  800  for initiating the operation of the polishing machine to start the polishing process after the settings are performed, and a stop button  810  for indicating stop operation. 
     The input method of the polishing conditions are that a ferrule type, φ 1.25 mm, for example, is first selected, and then the ferrule polishing condition is selected for APC polishing. Here, the polishing process steps and polishing time for each step are determined. Subsequently, the number of ferrules fixed to the jig is selected. The manipulations described above determine the load applied by the polishing machine. 
     In addition to this, a rotation control part for controlling the rotation speed of rotation and revolution for the polishing plate and a rotation number input part for inputting the rotation number to the rotation control part are disposed to control the rotation number of the polishing plate other than polishing pressure and polishing time, whereby further accurate end face polishing can be performed. 
     Examples of input by each button, changes in the display colors of the buttons, and indications by lighting have been described so far, but addition of a speech generation device or speech recognition process may allow speech input, speech announce, and calling attention. 
     Furthermore, the window size, arrangement, and screen switching of each indication part can be performed freely such that the display screens are rotated forward by the hour and that actual values in process conditions are displayed in graph to indicate a red line for easy observation of variations in status when a greater undershoot or overshoot causes a large deviation from the set value. Moreover, when particularly abnormal circumstances are generated, the control machine allows e-mail transmission to a cellular phone that an operator in charge has or another terminal that the operator has for sure emergency stop. 
     In this manner, according to the end face polishing machine of the invention, the control of a pressure in pressing the end face of the ferrule W onto the polishing sheet  70  is allowed. When the pressure in pressing the end face of the ferrule W is set low in starting polishing, scratches on the end face of the ferrule W can be prevented from being generated. 
     According to the invention, the polishing operation status such as the number of products can be decided and controlled from remote locations immediately because of the connection to the communication system through the LAN or Internet. Furthermore, the process management and production control over the respective factories having a plurality of subunits are allowed to facilitate the overall time management from order to production. Moreover, order and accounting systems are connected to complete the production control system for the overall factories. 
     Besides, variations in row material properties due to material lots of ferrules, and variation due to polishing media, temperatures, humidities, frictions of the polishing machine, and moments of the jig are finely adjusted, allowing improvement in yields.