CN102107305A - Underwater high-precision hole forming method based on electrical discharge machining - Google Patents
Underwater high-precision hole forming method based on electrical discharge machining Download PDFInfo
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- CN102107305A CN102107305A CN2009102597995A CN200910259799A CN102107305A CN 102107305 A CN102107305 A CN 102107305A CN 2009102597995 A CN2009102597995 A CN 2009102597995A CN 200910259799 A CN200910259799 A CN 200910259799A CN 102107305 A CN102107305 A CN 102107305A
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Abstract
The invention belongs to the technical field of electrical discharge machining, in particular to an underwater high-precision hole forming method based on electrical discharge machining, and aims to provide a method for forming a high-precision hole underwater under high irradiation conditions by electrical discharge machining, which can meet both requirements of the processing precision and processing speed. The method comprises the following steps: adjusting the process environment, setting rough processing parameters, performing rough processing twice, setting fine processing parameters, and performing fine processing twice. The invention has the advantages that: the rapid and high-precision hole processing is achieved by adopting the optimized electrical discharge machining parameters and the special design of the electrode scour hole, performing the rough processing twice and performing the fine processing twice. The processing depth of the threaded bottom hole is ensured, the degree of taper of the threaded bottom hole is reduced, and the risk that the screw tap is broken during the long-distance underwater tapping process is reduced. The smoothness of the processed surface is improved and a certain over-cut amount is provided, so that the processed threaded bottom hole can fully meet the requirement for engineering applications. The working current is increased to increase the speed of the electrical discharge machining.
Description
Technical field
The invention belongs to the spark erosion technique field, be specifically related in the high radiation environment manufacturing process of electric spark high accurate hole under water.
Background technology
Spark-erosion sinking processing (Electrical Discharge Machining, EDM) be the localized hyperthermia's fusing and gasification machined material fast that utilizes pulsed discharge to produce, thereby reaching a kind of process of removing material and processing, is one of special process method that is most widely used.
In the high radiation environment of nuclear power station, radioactivity equipment is carried out the shaping processing of thread Pilot hole, dowel hole or other shapes, in order to shield radioactivity, adopt at a distance spark-erosion sinking processing mode under water usually.Nuclear power station is used for shielding the boric acid that radioactive demineralized water contains finite concentration (2400ppm), and spark machined must be carried out in such boron water.The chip that spark machined produces directly is discharged in the boron water, will cause that the boracic electrical conductivity of water increases, and then have influence on the precision of spark machined.In order to guarantee the proportion of goods damageds of certain machining accuracy, speed, the mistake amount of cutting and electrode, electrical discharge machining process and parameter setting under water, need take all factors into consideration of the influence of the such overall situation of high radioactivity and boron water to EDM, control the boracic electrical conductivity of water, in time remove the radioactive debris that electric spark produces, also will shorten the activity duration in the high radioactivity environment simultaneously, this is the comparison difficulty technically as far as possible.
Repair special-purpose conveying, location and auxiliary shoring system (HDS) under water by means of the nuclear power station in-pile component, spark-erosion sinking processing (EDM) frock is accurately sent to position to be processed (the following 7m of the water surface).The invention provides a kind of effective ways of the high accuracy of the electric spark under water shaping processing of on reactor hanging basket outer wall, carrying out screwed hole, dowel hole etc., and be successfully applied to the transformation reparation of Pakistani C1 project irradiation pipe holder.Through consulting amount of literature data, the at present domestic good method of still not having the similar field engineering problem of solution.Comparing immediate domestic prior art scheme with the technical program is, indoor, adopts the kerosene medium, and the best surface smoothness that can obtain is near 6.3, and only about 10A, its process velocity is very slow to operating current at this moment.
Summary of the invention
The purpose of this invention is to provide a kind ofly under high radiation parameter, the manufacturing process of electric spark high accurate hole satisfies the requirement of machining accuracy and process velocity simultaneously under water.
The present invention is achieved in that a kind of high accurate hole of electric spark under water manufacturing process, comprises the steps:
In the step 1, cleaning water quality is opened dust catcher under water; Monitor the boracic electrical conductivity of water simultaneously, electrical conductivity maintains 4～7 μ S/cm (25 ℃);
In the step 2, the roughing electrode is installed; Electrode material is a graphite, connects positive polarity during work, and work piece is a stainless steel, connects negative polarity during work;
During roughing, servo velocity is arranged between 10mm/h～20mm/h; Electrode gap by executing agency according to setting the operating current adjustment, when the real work current value when setting operating current, executing agency increases electrode gap, operating current is reduced, too small when operating current, executing agency reduces electrode gap, and operating current is increased;
Step 3, the spark-erosion sinking processing tool is accurately sent to position to be processed;
In the step 4, at first open underwater television system, confirm the editing objective correct position, and monitoring electrode feed motion situation; After water quality is qualified, under the auxiliary supervision of TV, begin spark machined under water under water;
Under water during the spark machined, with oscillograph monitoring electrode gap voltage waveform, with the edm process of the auxiliary supervision of camera system under water; According to the discharge waveform situation of change that oscillograph shows, at any time servo velocity and electrode gap are done suitably small adjustment, guarantee that process is steady;
Step 5, the spark-erosion sinking processing tool is moved to waterborne, change the roughing electrode;
Step 6, repeating step 3 and step 4;
Step 7, the spark-erosion sinking processing tool is moved to waterborne, the fine finishining electrode is installed; Electrode material is a graphite, connects positive polarity during work, and the hanging basket material is a stainless steel, connects negative polarity during work;
During fine finishining, servo velocity is set to 4～8 times of roughing speed; Electrode gap by executing agency according to setting the operating current adjustment, when the real work current value when setting operating current, executing agency increases electrode gap, operating current is reduced, too small when operating current, executing agency reduces electrode gap, and operating current is increased;
Step 8, the spark-erosion sinking processing tool is accurately sent to position to be processed;
In the step 9, after the beginning fine finishining, open underwater television system, confirm the editing objective correct position, and monitoring electrode feed motion situation; After water quality is qualified, under the auxiliary supervision of TV, begin spark machined under water under water;
Under water during the spark machined, with oscillograph monitoring electrode gap voltage waveform, with the edm process of the auxiliary supervision of camera system under water; To do suitably small adjustment to servo velocity and electrode gap at any time according to the discharge waveform situation of change of oscillograph demonstration, guarantee that process is steady;
Wash away with demineralized water, as described in Table 2, the pressure and the flow of assurance flush water are in time discharged the chip that electric spark produces; Simultaneously, the chip that produces with the spark machined of dust catcher filtering under water;
During the spark machined, the periodic monitoring electrical conductivity of water by regulating the dust catcher and the Water of Power Plant circulatory system under water, makes electrical conductivity of water maintain 4～7 μ S/cm.
Step 10, the spark-erosion sinking processing tool is moved to waterborne, change the fine finishining electrode;
Step 11, repeating step 8 and step 9 are finished the processing in hole.
The aforesaid a kind of high accurate hole of electric spark under water manufacturing process, wherein,
In step 2, it is as shown in table 1 that the roughing parameter is set;
Table 1 hole roughing EDM parameter list
| Sequence number | Project name | Setting value (or show value) |
| 1 | Starting the arc gap voltage (V) | 300 |
| 2 | Electrode material | Graphite |
| 3 | Arc duration (μ S) | 128 |
| 4 | The time multiplier | 1.4 |
| 5 | Peak point current | 32A |
| 6 | Pulse voltage dutycycle (%) | 30 |
| 7 | Polarity of electrode | + |
| 8 | Operating current (A) | (28) |
| 9 | Working (machining) efficiency (%) | (48) |
| 10 | Oil pump outlet pressure (psi) | (420) |
| 11 | Flush water pressure (psi) | (90) |
| 12 | Flush water flow (gpm) | (1.5) |
| 13 | Dust catcher flow (gpm) under water | (500) |
| 14 | Demineralized water electrical conductivity (μ S/cm) | (4) |
In the last table, the 1st to the 7th was provided with before process begins and finishes for setting value, and the 8th to the 14th is adjusted value, and after promptly process began, Sustainable Control maintained near the set-point each parameter;
In step 4, beginning roughing; Wash away with demineralized water, described according to table 1, the pressure and the flow of assurance flush water are in time discharged the chip that electric spark produces; Simultaneously, the chip that produces with the spark machined of dust catcher filtering under water;
During the spark machined, the periodic monitoring electrical conductivity of water by regulating the dust catcher and the Water of Power Plant circulatory system under water, makes electrical conductivity of water maintain 4～7 μ S/cm;
In step 7, it is as shown in table 2 that the fine finishining parameter is set;
Table 2 hole fine finishining EDM parameter list
| Sequence number | Project name | Setting value (or show value) |
| 1 | Starting the arc gap voltage (V) | 300 |
| 2 | Electrode material | Graphite |
| 3 | Arc duration (μ S) | 128 |
| 4 | The time multiplier | 1.4 |
| 5 | Peak point current | 32A |
| 6 | Pulse voltage dutycycle (%) | 28 |
| 7 | Polarity of electrode | + |
| 8 | Operating current (A) | (24) |
| 9 | Working (machining) efficiency (%) | (40) |
| 10 | Oil pump outlet pressure (psi) | (420) |
| 11 | Flush water pressure (psi) | (90) |
| 12 | Flush water flow (gpm) | (1.5) |
| 13 | Dust catcher flow (gpm) under water | (490) |
| 14 | Demineralized water electrical conductivity (μ S/cm) | (4) |
In the last table, the 1st to the 7th was provided with before process begins and finishes for setting value, and the 8th to the 14th is adjusted value, and after promptly process began, Sustainable Control maintained near the set-point each parameter.
The aforesaid a kind of high accurate hole of electric spark under water manufacturing process, wherein, the roughing electrode washes away mode for the end face porous, and the roughing electrode is divided into three cylindrical sections that diameter becomes greatly successively, length shortens successively: gripping section, changeover portion and processing sections; Its center has the total runner of flush water that runs through gripping section, changeover portion and extend to the active section centre position; In active section, be starting point with the end face in above-mentioned hole, be terminal point with the outer face of active section, have 9 flush water branch flow passages again;
9 branch flow passages are as follows at the outer face of active section position of opening: 1 aperture is positioned at the center of circle of active section outer face, the center of circle that 4 apertures are evenly arranged in the active section outer face is on the less same circumference of the center of circle, radius, and the center of circle that other 4 apertures are evenly arranged in the active section outer face is on the bigger another one circumference of the center of circle, radius; On the outer face, the angle that forms between the aperture on any 1 aperture on the small circumference and the line in the center of circle and line is adjacent therewith the big circumference and the line in the center of circle is 45 °;
The hole of terminal point on the bigger circumference of radius becomes 15 ° angle with the central axis of electrode, and the hole of terminal point on the less circumference of radius becomes 5 ° angle with the central axis of electrode;
The roughing electrode is divided into three cylindrical sections that diameter becomes greatly successively, length shortens successively: gripping section, changeover portion and processing sections for the end face single hole washes away mode; Its center has the total runner of flush water that runs through gripping section, changeover portion and extend to the active section centre position.
The aforesaid a kind of high accurate hole of electric spark under water manufacturing process, wherein, the discharge channel of control power supply adopts 3.
Advantage of the present invention is: at being with radioactive workpiece, shield radioactivity by means of boron water; By special transportation under water, location and auxiliary grasping system, the EDM frock is accurately located under water; The design of spark machined parameter of having optimized by use and special electrode scour hole carries out twice roughing and twice fine finishining, obtained fast, the processing of high accurate hole.
Realized in the high radioactivity environment engineering practical application of M20 thread Pilot hole high accuracy processing on the large-scale component under water; By twice roughing and twice accurately machined technology, guarantee the working depth of thread Pilot hole, reduced the tapering of thread Pilot hole, the risk of screw tap fracture when having reduced tapping under water at a distance; The design of spark machined parameter of having optimized by use and special electrode scour hole improves scouring effect, has improved the fineness of finished surface on the one hand, has guaranteed certain mistake amount of cutting, and makes the thread Pilot hole of processing satisfy the requirement that engineering is used fully; On the other hand, obtain bigger operating current, accelerated the speed of spark-erosion sinking processing.
Description of drawings
Fig. 1 is an electric spark high accurate hole manufacturing process flow chart under water;
Fig. 2 is the roughing electrode structural chart;
Fig. 3 is the left view of Fig. 2;
Fig. 4 is the right view of Fig. 2;
Fig. 5 is the A-A profile among Fig. 3;
Fig. 6 is the left view of Fig. 5;
Fig. 7 is the B-B profile among Fig. 3;
Fig. 8 is the left view of Fig. 7;
Fig. 9 is the fine finishining electrode structural chart;
Figure 10 is the left view of Fig. 9;
Figure 11 is the right view of Fig. 9.
The specific embodiment
The present invention is described further below in conjunction with the drawings and specific embodiments:
With on the nuclear reactor hanging basket outer wall under water, the spark-erosion sinking under water of M20 thread Pilot hole is processed as example, need process the M20 thread Pilot hole on the hanging basket outer wall, as shown in Figure 1, adopt two times roughing and two times accurately machined modes to be shaped, the specific implementation process is as follows:
Step 1, since processing in boron water, carry out, at first open dust catcher under water, start the Water of Power Plant circulatory system in case of necessity, absorption may influence the impurity of processing, makes water quality limpid to carrying out spark machined; Need to monitor the boracic electrical conductivity of water simultaneously, electrical conductivity maintains 4～7 μ S/cm (25 ℃);
Step 2, installation roughing electrode; Electrode material is a graphite, connects positive polarity during work, and the hanging basket material is a stainless steel, connects negative polarity during work.It is as shown in table 1 that the roughing parameter is set;
Table 1M20 thread Pilot hole roughing EDM parameter list
| Sequence number | Project name | Setting value (or show value) |
| 1 | Starting the arc gap voltage (V) | 300 |
| 2 | Electrode material | Graphite |
| 3 | Arc duration (μ S) | 128 |
| 4 | The time multiplier | 1.4 |
| 5 | Peak point current | 32A |
| 6 | Pulse voltage dutycycle (%) | 30 |
| 7 | Polarity of electrode | + |
| 8 | Operating current (A) | (28) |
| 9 | Working (machining) efficiency (%) | (48) |
| 10 | Oil pump outlet pressure (psi) | (420) |
| 11 | Flush water pressure (psi) | (90) |
| 12 | Flush water flow (gpm) | (1.5) |
| 13 | Dust catcher flow (gpm) under water | (500) |
| 14 | Demineralized water electrical conductivity (μ S/cm) | (4) |
In the last table, the 1st to the 7th is to be provided with to finish before process begins for setting value, and the 8th to the 14th is adjusted value, after promptly process begins, need constantly to control each parameter is maintained near the set-point, thus the operation of stable electrical spark.
In addition, also have two in process, to need the parameter of adjustment in real time:
1, servo velocity:
During roughing, servo velocity is arranged between 10mm/h～20mm/h, and concrete value is decided on the condition that adds man-hour, when operating current excessive, the corresponding servo velocity that reduces of executing agency then, when operating current too small, the corresponding increase servo velocity of executing agency then.
2, electrode gap:
When the distance between electrode and the work piece reaches certain little value, electric discharge phenomena can appear, discharge current can appear, so operating current can characterize the gap between electrode and the workpiece fully, so its control is got final product according to operating current fully.
In contrast to the operating current of setting, when working current value excessive, the corresponding increase electrode gap of executing agency then, when operating current too small, the corresponding electrode gap that reduces of executing agency then.
When washing away, oil pump outlet pressure (psi), flush water pressure (psi), flush water flow (gpm) obtain by regulating.Such as, the oil pump outlet pressure behind pump start, can be regulated by the pressure-reducing valve of regulating pump discharge; Flush water pressure can be regulated by the aperture of regulating shunt valve, and the flow of flush water also can be regulated by the aperture of regulating outlet valve.The flow of dust catcher need not to regulate under water, only do and monitor usefulness, increase along with running time, the flow of flush water can descend gradually from 500gpm, can not continue to play good dust suction and do the time spent when this flow drops to, promptly need to change filter element for dust collector, general, when dust catcher flow under water drops to below 50% of initial value, promptly need more renew cartridge.
The roughing electrode design is washed away mode for the end face porous, and to improve scouring effect, electrode structure is seen accompanying drawing 2～8; The diameter of roughing electrode processing sections is 15.9mm, and the roughing electrode is divided into three cylindrical sections that diameter becomes greatly successively, length shortens successively: gripping section, changeover portion and processing sections; Its center has the total runner of flush water that runs through gripping section, changeover portion and extend to the active section centre position; In active section, be starting point with the end face in above-mentioned hole, be terminal point with the outer face of active section, have 9 flush water branch flow passages again;
9 branch flow passages are as follows at the outer face of active section position of opening: 1 aperture is positioned at the center of circle of active section outer face, the center of circle that 4 apertures are evenly arranged in the active section outer face is on the less same circumference of the center of circle, radius, and the center of circle that other 4 apertures are evenly arranged in the active section outer face is on the bigger another one circumference of the center of circle, radius; On the outer face, the angle that forms between the aperture on any 1 aperture on the small circumference and the line in the center of circle and line is adjacent therewith the big circumference and the line in the center of circle is 45 °.
The hole of terminal point on the bigger circumference of radius becomes 15 ° angle with the central axis of electrode, and the hole of terminal point on the less circumference of radius becomes 5 ° angle with the central axis of electrode.
The advantage of this kind structure is: (1) total flow diameter is bigger, and runner is long, and the processing of electrode runner is convenient in design so on the one hand; On the other hand, when flush water was flowed through total runner, resistance was little, and the pressure loss is little; (2) because each branch flow passage diameter is little, the flush water flow is little, so a plurality of branch flow passages of processing are guaranteed enough total flush water flows; (3) branch flow passage is shorter, and is respectively 0 °, 5 ° and 15 ° with the central axis angle, makes things convenient for the processing of electrode runner; (4) except the branch flow passage by the center of circle, all the other 8 runners and central axis have angle, have played guide effect, make water flow out electrode after, radially evenly wash away outward, improved scouring effect; (5) branch flow passage becomes certain included angle with central axis, has eliminated in the process, and " burr " that produces in the scour hole position improved processing effect.
Step 3, repair special-purpose conveying, location and auxiliary shoring system under water, the spark-erosion sinking processing tool is accurately sent to position to be processed (the following about 7m of the water surface) by means of the nuclear power station in-pile component.
Step 4, beginning roughing.
Open underwater television system, confirm the editing objective correct position, and monitoring electrode feed motion situation.After water quality is qualified, under the auxiliary supervision of TV, can begin spark machined under water under water.
Under water during the spark machined, with oscillograph monitoring electrode gap voltage waveform, with the edm process of the auxiliary supervision of camera system under water; To do suitably small adjustment to servo velocity and electrode gap at any time according to the discharge waveform situation of change of oscillograph demonstration, guarantee that process is steady;
Wash away with demineralized water, described according to table 1, the pressure and the flow of assurance flush water are in time discharged the chip that electric spark produces; Simultaneously, the chip that produces with the spark machined of dust catcher filtering under water;
During the spark machined, the periodic monitoring electrical conductivity of water by regulating the dust catcher and the Water of Power Plant circulatory system under water, makes electrical conductivity of water maintain 4～7 μ S/cm.
Step 5, the spark-erosion sinking processing tool is moved to waterborne, change the roughing electrode;
Step 6, repeating step 3 and step 4;
Step 7, the spark-erosion sinking processing tool is moved to waterborne, the fine finishining electrode is installed; Electrode material is a graphite, connects positive polarity during work, and the hanging basket material is a stainless steel, connects negative polarity during work.It is as shown in table 2 that the fine finishining parameter is set;
Table 2M20 thread Pilot hole fine finishining EDM parameter list
| Sequence number | Project name | Setting value (or show value) |
| 1 | Starting the arc gap voltage (V) | 300 |
| 2 | Electrode material | Graphite |
| 3 | Arc duration (μ S) | 128 |
| 4 | The time multiplier | 1.4 |
| 5 | Peak point current | 32A |
| 6 | Pulse voltage dutycycle (%) | 28 |
| 7 | Polarity of electrode | + |
| 8 | Operating current (A) | (24) |
| 9 | Working (machining) efficiency (%) | (40) |
| 10 | Oil pump outlet pressure (psi) | (420) |
| 11 | Flush water pressure (psi) | (90) |
| 12 | Flush water flow (gpm) | (1.5) |
| 13 | Dust catcher flow (gpm) under water | (490) |
| 14 | Demineralized water electrical conductivity (μ S/cm) | (4) |
The fine finishining electrode design is washed away mode for the end face single hole, and to reduce to wash away resistance, electrode structure is seen accompanying drawing 9～11.Fine finishining electrode active section diameter is 17.3mm.
In addition, also have two in process, to need the parameter of adjustment in real time:
1, servo velocity:
During fine finishining, servo velocity can be taken as 4～8 times of roughing speed, and concrete value is decided on the condition that adds man-hour, when operating current excessive, the corresponding servo velocity that reduces of executing agency then, when operating current too small, the corresponding increase servo velocity of executing agency then.
2, electrode gap:
When the distance between electrode and the work piece reaches certain little value, electric discharge phenomena can appear, discharge current can appear, so operating current can characterize the gap between electrode and the workpiece fully, so its control is got final product according to operating current fully.
In contrast to the operating current of setting, when working current value excessive, the corresponding increase electrode gap of executing agency then, when operating current too small, the corresponding electrode gap that reduces of executing agency then.
Step 8, repair special-purpose conveying, location and auxiliary shoring system under water, the spark-erosion sinking processing tool is accurately sent to position to be processed (the following about 7m of the water surface) by means of the nuclear power station in-pile component.
Step 9, beginning fine finishining.
Open underwater television system, confirm the editing objective correct position, and monitoring electrode feed motion situation.After water quality is qualified, under the auxiliary supervision of TV, begin spark machined under water under water.
Under water during the spark machined, with oscillograph monitoring electrode gap voltage waveform, with the edm process of the auxiliary supervision of camera system under water; To do suitably small adjustment to servo velocity and electrode gap at any time according to the discharge waveform situation of change of oscillograph demonstration, guarantee that process is steady;
Wash away with demineralized water, as described in Table 2, the pressure and the flow of assurance flush water are in time discharged the chip that electric spark produces; Simultaneously, the chip that produces with the spark machined of dust catcher filtering under water;
During the spark machined, the periodic monitoring electrical conductivity of water by regulating the dust catcher and the Water of Power Plant circulatory system under water, makes electrical conductivity of water maintain 4～7 μ S/cm.
Step 10, the spark-erosion sinking processing tool is moved to waterborne, change the fine finishining electrode;
Step 11, repeating step 8 and step 9.
After second time fine finishining is finished, the screwed hole that processes is washed cleaning,, confirm the cleannes of thread Pilot hole with camera system inspection under water with giant.
Whole process must have the special messenger to guard, and the flow of periodic monitoring dust catcher and boracic electrical conductivity of water after the dust catcher flow reduces, need in time more renew cartridge.
Pressure, flow and the record of periodic monitoring EDM hydraulic pump outlet pressure and demineralized water confirm that these parameters all keep normal stable.
In said method, in order further to improve processing stability and to improve working power, adding man-hour, the discharge channel of control power supply adopts 3.
By the inventive method, obtained bigger operating current and higher surface smoothness: when processing the thread Pilot hole of M20, the roughing electric current has reached 28～30A, and the fine finishining electric current has reached 24～26A.After second time fine finishining is finished, after testing, the thread Pilot hole hole depth 50mm of processing, aperture 17.5mm, crossing the amount of cutting is 0.1mm, surface smoothness is better than 6.3, satisfies the tapping requirement fully.Successfully realized the shaping of the high accuracy under water processing of 48 M20 thread Pilot holes on reactor hanging basket outer wall.
Conclusion is got up, and the reason that obtains above-mentioned advantage mainly contains the following aspects:
(1), optimized electrode structure;
(2), the EDM parameter of You Huaing;
(3), the processing technology of twice of twice of roughing and fine finishining;
(4), with oscillograph monitoring electrode gap voltage waveform, with the edm process of the auxiliary supervision of camera system under water; At any time servo velocity and electrode gap are done suitably small adjustment, guarantee that process is steady.
Claims (4)
1. an electric spark high accurate hole manufacturing process under water comprises the steps:
In the step 1, cleaning water quality is opened dust catcher under water; Monitor the boracic electrical conductivity of water simultaneously, electrical conductivity maintains 4～7 μ S/cm (25 ℃);
In the step 2, the roughing electrode is installed; Electrode material is a graphite, connects positive polarity during work, and work piece is a stainless steel, connects negative polarity during work;
During roughing, servo velocity is arranged between 10mm/h～20mm/h; Electrode gap by executing agency according to setting the operating current adjustment, when the real work current value when setting operating current, executing agency increases electrode gap, operating current is reduced, too small when operating current, executing agency reduces electrode gap, and operating current is increased;
Step 3, the spark-erosion sinking processing tool is accurately sent to position to be processed;
In the step 4, at first open underwater television system, confirm the editing objective correct position, and monitoring electrode feed motion situation; After water quality is qualified, under the auxiliary supervision of TV, begin spark machined under water under water;
Under water during the spark machined, with oscillograph monitoring electrode gap voltage waveform, with the edm process of the auxiliary supervision of camera system under water; According to the discharge waveform situation of change that oscillograph shows, at any time servo velocity and electrode gap are done suitably small adjustment, guarantee that process is steady;
Step 5, the spark-erosion sinking processing tool is moved to waterborne, change the roughing electrode;
Step 6, repeating step 3 and step 4;
Step 7, the spark-erosion sinking processing tool is moved to waterborne, the fine finishining electrode is installed; Electrode material is a graphite, connects positive polarity during work, and the hanging basket material is a stainless steel, connects negative polarity during work;
During fine finishining, servo velocity is set to 4～8 times of roughing speed; Electrode gap by executing agency according to setting the operating current adjustment, when the real work current value when setting operating current, executing agency increases electrode gap, operating current is reduced, too small when operating current, executing agency reduces electrode gap, and operating current is increased;
Step 8, the spark-erosion sinking processing tool is accurately sent to position to be processed;
In the step 9, after the beginning fine finishining, open underwater television system, confirm the editing objective correct position, and monitoring electrode feed motion situation; After water quality is qualified, under the auxiliary supervision of TV, begin spark machined under water under water;
Under water during the spark machined, with oscillograph monitoring electrode gap voltage waveform, with the edm process of the auxiliary supervision of camera system under water; To do suitably small adjustment to servo velocity and electrode gap at any time according to the discharge waveform situation of change of oscillograph demonstration, guarantee that process is steady;
Wash away with demineralized water, as described in Table 2, the pressure and the flow of assurance flush water are in time discharged the chip that electric spark produces; Simultaneously, the chip that produces with the spark machined of dust catcher filtering under water;
During the spark machined, the periodic monitoring electrical conductivity of water by regulating the dust catcher and the Water of Power Plant circulatory system under water, makes electrical conductivity of water maintain 4～7 μ S/cm.
Step 10, the spark-erosion sinking processing tool is moved to waterborne, change the fine finishining electrode;
Step 11, repeating step 8 and step 9 are finished the processing in hole.
2. a kind of high accurate hole of electric spark under water manufacturing process as claimed in claim 1 is characterized in that:
In step 2, it is as shown in table 1 that the roughing parameter is set;
Table 1 hole roughing EDM parameter list
In the last table, the 1st to the 7th was provided with before process begins and finishes for setting value, and the 8th to the 14th is adjusted value, and after promptly process began, Sustainable Control maintained near the set-point each parameter;
In step 4, beginning roughing; Wash away with demineralized water, described according to table 1, the pressure and the flow of assurance flush water are in time discharged the chip that electric spark produces; Simultaneously, the chip that produces with the spark machined of dust catcher filtering under water;
During the spark machined, the periodic monitoring electrical conductivity of water by regulating the dust catcher and the Water of Power Plant circulatory system under water, makes electrical conductivity of water maintain 4～7 μ S/cm;
In step 7, it is as shown in table 2 that the fine finishining parameter is set;
Table 2 hole fine finishining EDM parameter list
In the last table, the 1st to the 7th was provided with before process begins and finishes for setting value, and the 8th to the 14th is adjusted value, and after promptly process began, Sustainable Control maintained near the set-point each parameter.
3. as claim 1 or the 2 described a kind of high accurate hole of electric spark under water manufacturing process, it is characterized in that: the roughing electrode washes away mode for the end face porous, and the roughing electrode is divided into three cylindrical sections that diameter becomes greatly successively, length shortens successively: gripping section, changeover portion and processing sections; Its center has the total runner of flush water that runs through gripping section, changeover portion and extend to the active section centre position; In active section, be starting point with the end face in above-mentioned hole, be terminal point with the outer face of active section, have 9 flush water branch flow passages again;
9 branch flow passages are as follows at the outer face of active section position of opening: 1 aperture is positioned at the center of circle of active section outer face, the center of circle that 4 apertures are evenly arranged in the active section outer face is on the less same circumference of the center of circle, radius, and the center of circle that other 4 apertures are evenly arranged in the active section outer face is on the bigger another one circumference of the center of circle, radius; On the outer face, the angle that forms between the aperture on any 1 aperture on the small circumference and the line in the center of circle and line is adjacent therewith the big circumference and the line in the center of circle is 45 °;
The hole of terminal point on the bigger circumference of radius becomes 15 ° angle with the central axis of electrode, and the hole of terminal point on the less circumference of radius becomes 5 ° angle with the central axis of electrode;
The roughing electrode is divided into three cylindrical sections that diameter becomes greatly successively, length shortens successively: gripping section, changeover portion and processing sections for the end face single hole washes away mode; Its center has the total runner of flush water that runs through gripping section, changeover portion and extend to the active section centre position.
4. a kind of high accurate hole of electric spark under water manufacturing process as claimed in claim 3 is characterized in that: the discharge channel of control power supply adopts 3.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103551683A (en) * | 2013-11-05 | 2014-02-05 | 常州工学院 | Electrode gap control method and device for numerical control electrolytic machining |
| CN104668682A (en) * | 2015-03-09 | 2015-06-03 | 成都科力铁硬质合金有限公司 | Method and tooling for electric spark machining of internal thread of hard alloy product |
| CN112355415A (en) * | 2020-11-10 | 2021-02-12 | 西安赛福斯材料防护有限责任公司 | Manual machining method for precise threads of titanium-based parts |
-
2009
- 2009-12-24 CN CN200910259799A patent/CN102107305B/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103551683A (en) * | 2013-11-05 | 2014-02-05 | 常州工学院 | Electrode gap control method and device for numerical control electrolytic machining |
| CN104668682A (en) * | 2015-03-09 | 2015-06-03 | 成都科力铁硬质合金有限公司 | Method and tooling for electric spark machining of internal thread of hard alloy product |
| CN104668682B (en) * | 2015-03-09 | 2017-01-11 | 成都科力铁硬质合金有限公司 | Method and tooling for electric spark machining of internal thread of hard alloy product |
| CN112355415A (en) * | 2020-11-10 | 2021-02-12 | 西安赛福斯材料防护有限责任公司 | Manual machining method for precise threads of titanium-based parts |
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| CN102107305B (en) | 2012-10-10 |
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