Machining method for correcting out-of-tolerance of wall thickness difference of cast pipe die

Abstract

The invention relates to a processing method for correcting wall thickness difference out-of-tolerance of a cast pipe die with an inner hole diameter of phi 180mm-phi 300mm. When the inner hole of the cast pipe die is processed, the wall thickness difference out-of-tolerance at a position about 1500-2000mm away from a mark end is often caused due to material core bending and inner hole deflection caused by sleeving the inner hole, if the inner hole is continuously sleeved, the inner hole is more deflected, and the inner hole is prevented from deviating. A workpiece is corrected through an upper oil pressure straightening machine, the thickest wall thickness position of the cast pipe die is pressed and corrected to be a high point, the workpiece is turned on a lathe after being pressed and corrected, it is guaranteed that the wall thickness difference at the frame position is smaller than or equal to 1.5 mm, then the frame position is supported by a center frame, the outer circle is roughly turned after the machining allowance of 7 mm is reserved for the outer circle, and the outer circle is machined. And the workpiece is aligned by an outer circle on a deep hole drilling and boring machine, a phi (D-10) mm hole is aligned, an inner hole is drilled through, a material core falls, a phi Dmm through hole is bored after turning around, and then the workpiece is turned by a lathe to form an outer circle, so that the wall thickness difference requirement of the whole length of the cast pipe die is ensured, the wall thickness difference requirement of the cast pipe die is ensured, and the product processing quality is saved.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanical processing, and in particular relates to a processing method for correcting excessive wall thickness difference of a pipe casting mold with an inner hole diameter of φ180mm to φ300mm. Background Art

[0002] Processing Figure 1 The cast pipe mold shown is 6 to 7 meters long and has a through hole with an inner diameter of φ180mm to φ300mm. This deep hole of the cast pipe mold is usually processed on a deep hole boring machine. The drill is drilled from the stamped end and a φD sleeve cutter is used to cover the φD through hole. When the hole is cut, the inner hole is deflected due to the bending of the sleeved material core, which often causes the wall thickness difference at a position about 1500 to 2000mm from the stamped end to exceed the tolerance. The wall thickness difference is 12mm to 15mm, while the product processing technology requires that the wall thickness difference of the entire length of the cast pipe mold is only 3mm. If the hole is cut further, the inner hole will be more deflected, resulting in a wall thickness difference far greater than 15mm, while the outer diameter machining allowance of the cast pipe mold is usually 15mm, resulting in the wall thickness difference of the cast pipe mold exceeding the tolerance and being scrapped. In view of this, we need to design a processing method to correct the wall thickness difference of the cast pipe mold with an inner hole diameter of φ180mm to φ300mm. Summary of the invention

[0003] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a processing method for improving processing quality, reducing the wall thickness difference of the casting pipe mold, and correcting the excessive wall thickness difference of the casting pipe mold by performing rescue processing.

[0004] The technical solution of the present invention is achieved as follows: a processing method for correcting the over-tolerance of the wall thickness difference of the casting pipe mold, and a processing method for saving the inner hole deviation of the casting pipe mold with an inner hole diameter of φ180mm to φ300mm are specifically as follows: Step 1), along the outer circumference of the bottom of the blind hole of the cast pipe mold, use a wall thickness gauge to measure the wall thickness of the bottom of the blind hole of the cast pipe mold, and mark the thickest point and the wall thickness difference; Step 2), place the pipe casting mold with the thickest point marked on the hydraulic straightening machine for pressure calibration. First, straighten the pipe casting mold to meet the straightness of the entire length of the pipe casting mold ≤ 3mm, and then apply force F to press the thickest point of the pipe casting mold wall thickness as the high point. The runout of the high point is the wall thickness difference; Step 3), process the cast pipe mold after pressure calibration on a lathe, the four-jaw chuck of the lathe clamps the outer circle of the stamped end of the cast pipe mold, the tailstock top of the lathe supports the center hole of the non-marked end of the cast pipe mold, and the frame position is 1500-2000mm away from the stamped end of the cast pipe mold. By adjusting the four-jaw chuck, ensure that the wall thickness difference at the frame position is ≤1.5mm, and then support the frame position with a center frame, leave a 7mm machining allowance on the outer circle and then roughly turn the outer circle; Step 4), put the cast pipe mold after rough turning of the outer circle on the deep hole drilling and boring machine, align with the outer circle, and the full length outer circle runout is ≤0.5mm. The chuck of the deep hole drilling and boring machine clamps the outer circle, and drills from the non-marked end to cover the φ(D-10)mm inner hole, that is, the diameter of the inner hole is 10mm smaller than φD. After the inner hole of the cast pipe mold is covered, the core is taken out; Step 5) Turn the cast pipe mold on the deep hole drilling and boring machine, align it with the outer circle, and make the outer circle runout of the entire length ≤0.5mm. The chuck of the deep hole drilling and boring machine clamps the outer circle, and bores the through hole from the marked end with a φD quilling cutter; Step 6) Place the lathe on the machine, use the inner hole to position the outer circle of the casting pipe mold to the size required by the drawing.

[0005] The positive effects of the technical solution of the present invention are as follows: a processing method for rescuing the inner hole deviation of a pipe casting mold with an inner hole diameter of φ180mm to φ300mm, solving the problem of excessive inner hole wall thickness difference of the pipe casting mold. Figure 1 For the cast pipe mold shown in the figure, when the inner hole is φD in diameter, the inner hole is deviated due to the bending of the material core, and the wall thickness difference is out of tolerance at about 1500~2000mm away from the imprint end of the cast pipe mold. The wall thickness difference is 12mm~15mm, while the product processing technology requires that the wall thickness difference of the entire length of the cast pipe mold is only 3mm. If the hole is further cut, the inner hole will be more deviated, resulting in a wall thickness difference far greater than 15mm, while the outer circle machining allowance of the cast pipe mold is usually 15mm, resulting in the wall thickness difference of the cast pipe mold being out of tolerance and being scrapped.

[0006] Through this technical invention, the inner hole deflection caused by the bending of the core during trepanning, which would cause the wall thickness difference to exceed the tolerance and be scrapped, can be saved into a product with a qualified wall thickness difference. The inner hole misalignment and the workpiece wall thickness difference can be effectively reduced, so that the wall thickness difference of the cast pipe mold after processing is controlled within 3mm, achieving the effect of saving product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 Schematic diagram of the casting pipe mold.

[0008] Figure 2 It is a schematic diagram of the alignment of the present invention.

[0009] Figure 3 It is a schematic diagram of the frame position of the present invention.

[0010] Figure 4 It is a schematic diagram of the sleeve holes of the present invention.

[0011] As shown in the figure: 1. Core DETAILED DESCRIPTION

[0012] A processing method for correcting the excessive tolerance of the wall thickness difference of the cast pipe mold, and the processing method for saving the inner hole deviation of the cast pipe mold with an inner hole diameter of φ180mm to φ300mm is as follows: Step 1), along the outer circumference of the bottom of the blind hole of the cast pipe mold, use a wall thickness gauge to measure the wall thickness of the bottom of the blind hole of the cast pipe mold, and mark the thickest point and the wall thickness difference; Step 2) Place the pipe casting mold with the thickest point marked on the hydraulic straightening machine for pressure correction. Figure 2 First, straighten the pipe casting mold to ensure that the straightness of the entire length of the pipe casting mold is ≤3mm, and then apply force F to press the thickest point of the pipe casting mold wall to the high point. The runout of the high point is the wall thickness difference; Step 3) Process the calibrated casting tube mold on a lathe. The four-jaw chuck of the lathe clamps the outer circle of the stamped end of the casting tube mold. The tailstock top of the lathe supports the center hole of the non-stamped end of the casting tube mold. Figure 3 The position shown (about 1500-2000mm from the end of the casting mold mark) is the frame position. By adjusting the four-jaw chuck, ensure that the wall thickness difference at the frame position is ≤1.5mm. Then use the center frame to support the frame position, leave 7mm machining allowance on the outer circle and then rough turn the outer circle; Step 4) Process the pipe casting mold after rough turning on the outer circle on a deep hole drilling and boring machine. Figure 4 As shown in the figure, align the outer circle, the full-length outer circle runout is ≤0.5mm, the chuck of the deep hole drilling and boring machine clamps the outer circle, and drills from the non-marked end, and sets the φ(D-10)mm inner hole, that is, the diameter of the inner hole is 10mm smaller than φD. After the inner hole of the casting pipe mold is set through, take out the core; Step 5) Turn the cast pipe mold on the deep hole drilling and boring machine, align it with the outer circle, and make the outer circle runout of the entire length ≤0.5mm. The chuck of the deep hole drilling and boring machine clamps the outer circle, and bores the through hole from the marked end with a φD quilling cutter; Step 6) Place the lathe on the machine, use the inner hole to position the outer circle of the casting pipe mold to the size required by the drawing.

[0013] Example 1: Casting pipe mold: material is 21CrMo10; specification: the inner hole of the casting pipe mold is Φ190mm, and the length is 6300mm. When the casting pipe mold is sleeved with an inner hole of Φ190mm, the inner hole is deflected due to the bending of the core material, resulting in a wall thickness difference of 13mm at 1820mm from the imprint end, and the thickest part of the wall thickness is still the lowest point of the bending. If the inner hole is further processed, the hole will become more and more deflected, resulting in a larger wall thickness difference of the casting pipe mold and scrapping.

[0014] The specific processing process is as follows: Step 1) Measure the wall thickness of the bottom of the blind hole of the cast pipe mold (1820mm from the mark end) along the outer circumference of the bottom of the blind hole of the cast pipe mold with a wall thickness gauge, and mark the thickest point and the wall thickness difference of 13mm; Step 2) Place the pipe casting mold with the thickest point marked on the hydraulic straightening machine for pressure calibration. First, straighten the pipe casting mold to meet the straightness of the entire length of the pipe casting mold ≤ 3mm, and then press the thickest point of the pipe casting mold wall thickness as the high point, and the runout of the high point is 13mm; Step 3), process the cast pipe mold after pressure calibration on a lathe, the four-jaw chuck of the lathe clamps the outer circle of the marked end of the cast pipe mold, the tailstock top of the lathe supports the center hole of the non-marked end of the cast pipe mold, and the frame position is 1820mm away from the marked end of the cast pipe mold. By adjusting the four-jaw chuck, ensure that the wall thickness difference at the frame position is ≤1.5mm, and then support the frame position with a center frame, leave a 7mm machining allowance on the outer circle and then roughly turn the outer circle; Step 4) Place the cast pipe mold after rough turning on the outer circle on a deep hole boring and drilling machine. Align the outer circle and make the outer circle runout of the entire length ≤0.5mm. Clamp the outer circle with the chuck of the deep hole boring and drilling machine, and drill from the non-marked end. Sleeve the φ180mm inner hole. After the inner hole is penetrated, take out the core. Step 5) Turn the cast pipe mold on the deep hole drilling and boring machine, align it with the outer circle, and make the outer circle runout of the entire length ≤0.5mm. The chuck of the deep hole drilling and boring machine clamps the outer circle, and bores the through hole from the marked end with a φ190mm trepanning cutter; Step 6) Place the mold on a lathe and use the inner hole to position it, and lathe the outer circle of the casting pipe mold to the size required by the drawing. After processing, the wall thickness differences at three points along the entire length of the casting pipe mold are 1.4mm, 1.6mm, and 1.3mm, which satisfies the requirement that the wall thickness difference of the casting pipe mold be controlled within 3mm, thus achieving the effect of saving product quality.

Claims

1. A processing method for correcting the over-tolerance of the wall thickness difference of a pipe casting mold, characterized in that: the processing method for saving the inner hole deviation of a pipe casting mold with an inner hole diameter of φ180mm to φ300mm is as follows: Step 1), along the outer circumference of the bottom of the blind hole of the cast pipe mold, use a wall thickness gauge to measure the wall thickness of the bottom of the blind hole of the cast pipe mold, and mark the thickest point and the wall thickness difference; Step 2), place the pipe casting mold with the thickest point marked on the hydraulic straightening machine for pressure calibration. First, straighten the pipe casting mold to meet the straightness of the entire length of the pipe casting mold ≤ 3mm, and then apply force F to press the thickest point of the pipe casting mold wall thickness as the high point. The runout of the high point is the wall thickness difference; Step 3), process the cast pipe mold after pressure calibration on a lathe, the four-jaw chuck of the lathe clamps the outer circle of the stamped end of the cast pipe mold, the tailstock top of the lathe supports the center hole of the non-marked end of the cast pipe mold, and the frame position is 1500-2000mm away from the stamped end of the cast pipe mold. By adjusting the four-jaw chuck, ensure that the wall thickness difference at the frame position is ≤1.5mm, and then support the frame position with a center frame, leave a 7mm machining allowance on the outer circle and then roughly turn the outer circle; Step 4), put the cast pipe mold after rough turning of the outer circle on the deep hole drilling and boring machine, align with the outer circle, and the full length outer circle runout is ≤0.5mm. The chuck of the deep hole drilling and boring machine clamps the outer circle, and drills from the non-marked end to cover the φ(D-10)mm inner hole, that is, the diameter of the inner hole is 10mm smaller than φD. After the inner hole of the cast pipe mold is covered, the core is taken out; Step 5) Turn the cast pipe mold on the deep hole drilling and boring machine, align it with the outer circle, and make the outer circle runout of the entire length ≤0.5mm. The chuck of the deep hole drilling and boring machine clamps the outer circle, and bores the through hole from the marked end with a φD quilling cutter; Step 6) Place the lathe on the machine, use the inner hole to position the outer circle of the casting pipe mold to the size required by the drawing.

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