The principle of heavy-duty gear scraping: Heavy-duty gear scraping uses a cutting method that integrates hobbing and shaping to process internal and external cylindrical gears. During the cutting process, the cutting tool acts as both a hob and a shaper. The cutting method involves continuous rotation of the workpiece and the tool, combining the hobbing and shaping motions to cut the gears. During heavy-duty scraping, the tool has an axial angle relative to the workpiece and rotates around its own axis to generate motion. Simultaneously, the tool moves along the workpiece's axial direction to cut the entire length of the workpiece. The shape of the tool is very similar to that of a shaper. When the workpiece has spur teeth, the tool should be a beveled tooth; when the workpiece has beveled teeth, the tool is generally made into a spur tooth. When machining involute tooth profiles, regardless of whether the tool is a spur or beveled tooth, the tooth profile in its end face is involute. The theoretical cutting edge shape of the tool should be manufactured according to the contact line on the tool tooth surface when the tool and workpiece mesh. Therefore, when the tool is a spur tooth, the cutting edge is on the end face of the tool…

To address the problems encountered during the machining of sprocket shaft parts, the machining scheme was improved by adopting a combined machining method, which reduced the machining difficulty and cost, met the dimensional and precision requirements of the parts, and improved machining efficiency. The main function of the shaft is to support transmission components (gears, sprockets, and pulleys, etc.), transmit torque, and bear loads. Its main structural feature is that its length is greater than its diameter, and it is generally composed of a coaxial outer circle, a cone, an inner hole, threads, and keyways. 1. Analysis of Part Structure and Machining Difficulties The sprocket shaft is a slender shaft of the sprocket drive mechanism of the drying oven in our SPL-1200 printing system. The material is 45 steel, heat-treated (T215). The part has a diameter of 30mm, a length of 1171mm, and a length-to-diameter ratio of 39. It is a slender shaft with very poor rigidity. The machining requirements are a dimensional accuracy of φ30 0-0.009mm at both ends, and the coaxiality of the φ30mm outer circles at both ends…

Features of the WERA gear shifting machine from Germany: High machining precision, achieving DIN 5-7 grade accuracy; Surface roughness: Rz2-3; High flexibility: One machine can process both internal and external gears; High efficiency: Changeover time is within 30 minutes, requiring only tool replacement, chuck, conveyor mask, and program re-entry; Low tool consumption cost, reusable after repeated sharpening (15-20 times); Dry machining, no coolant required, saving production costs and reducing potential failure points; Clean and environmentally friendly machine tool, no post-processing cleaning required; Pneumatic clamping (5 bar air source), eliminating the need for a hydraulic system, saving production costs; Convenient for inline production: The machine's loading and unloading conveyor can be left-hand, right-hand, or continuous (preliminary confirmation required); …

Abnormal tooth profile – Tooth edge protrusion is mainly caused by excessive tooth profile error of the hob or inability to divide the teeth effectively. There are four types of workpiece defects: 1) Poor tooth division after hob grinding; 2) Excessive axial runout of the hob; 3) Large radial runout of the hob; 4) Dull hob. The main solutions are to focus on the hob grinding quality, hob installation accuracy, and machine tool spindle geometric accuracy: 1) Control the hob grinding quality; 2) Ensure the hob installation accuracy, and avoid hammering during hob installation; ensure the washer end face is flat; the nut end face is vertical; the inside of the taper hole is clean; and there should be no gap after the bracket is installed; 3) Recheck the rotation accuracy of the machine tool spindle and repair and adjust the hob spindle bearings, especially the thrust washer; 4) Replace with a new hob.

Abnormal Tooth Profile – Main Causes of Periodic Tooth Profile Errors: 1) Large radial runout or axial movement after hob installation; 2) Uneven rotation of the machine tool table; 3) Misalignment or tooth surface collision of the intermediate gear or indexing gear; 4) Loose tool holder slide; 5) Improper workpiece clamping causing vibration. Solutions: 1) Control the hob installation accuracy; 2) Check and adjust the axial movement of the machine tool table indexing worm gear; 3) Check the installation and operation of the intermediate gear and indexing gear; 4) Adjust the stoppers on the tool holder slide; 5) Select the correct workpiece clamping method.

Experimental Object and Methods Experimental Object: The experimental object in this paper is a sprocket, the structure of which is shown in Figure 1. The sprocket has 21 teeth, a pitch circle diameter of approximately 650 mm, an inner diameter of approximately 450 mm, a tooth thickness of approximately 65 mm, and a weight of approximately 50 kg. Technical requirements: quenching and tempering treatment, hardness 229～302HB (dB: 3.5～4.0), metallographic structure grade 1～4, grain size ≥5. Experimental Methods: Original sprocket manufacturing process: blanking → billet making → medium-frequency heating → forging → trimming → quenching and tempering → magnetic particle testing → grinding → surface quenching + low-temperature tempering → magnetic particle testing → machining. Residual heat quenching sprocket manufacturing process: blanking → billet making → medium-frequency heating → forging → trimming → residual heat quenching → high-temperature tempering → magnetic particle testing → grinding → surface quenching → low-temperature tempering → magnetic particle testing → machining. The sprocket material is 40Mn2, which has low hardening...

Common sprocket material: C45. Common sprocket machining methods: quenching and blackening treatment. General principles for selecting the number of sprocket teeth: 19 teeth or more are generally used for drive sprockets operating at medium to high speeds under normal working conditions. 17 teeth are only used for small-pitch drive sprockets. 23 teeth or more are recommended for impact applications. When the speed ratio is low, using a high-tooth-count sprocket can significantly reduce the rotational amount of the chain links, the tensile load on the chain, and the load on the bearings. Features: Compared with belt drives: 1. Sprocket drives have no elastic slippage or slippage, maintaining an accurate average transmission ratio; 2. Requires less tension, resulting in less pressure on the shaft and reducing bearing friction loss; 3. Compact structure; 4. Can work in harsh environments such as high temperatures and oil contamination; 5. Lower manufacturing and installation precision, simpler transmission structure when the center distance is large; Disadvantages: Instantaneous speed and instantaneous transmission…

Double-pitch sprockets, after prolonged use, will lack lubrication, increasing wear and shortening the lifespan of the chain and sprockets. Lubrication should only be applied to the chain and sprockets, but not excessively to prevent splattering; the chain and sprockets should not be greasy. This is the proper lubrication method. Chains and sprockets are used in various conveying machinery to provide power transmission, which is fundamental to the normal operation of conveying tools, and conveying tools are the foundation for the normal operation of various production lines. Therefore, sprockets are crucial for industrial production in various industries. Choosing a manufacturer is therefore very important. Double-pitch sprockets are particularly prone to damage during use. Therefore, double-pitch sprocket manufacturers usually remind buyers to first develop good sprocket usage habits, such as checking them promptly after starting and stopping the machine to ensure there is no damage, wear, or lack of lubrication. Secondly, attention should be paid to the environmental conditions in which the sprockets are used.