带式夹持输送对虾开背机的设计与试验

为适应不同尺寸对虾开背以及寻找开背的优化参数,设计带式夹持输送对虾开背机,并对该方案的夹持与输送机构、夹持V角调节机构、限深与导正部分进行了详细设计。在单因素试验的基础上,以响应面优化法安排三因素三水平的正交试验,探求了夹持V角、输送速度、切割转速3个关键参数对切口长度、切口对称度、切口深度、切口光滑度4个评价指标的影响规律,利用Design-Expert8.06软件对试验结果进行方差分析,建立了评价指标与各影响因素的数学回归模型,并进行响应面分析,得到带式对虾开背机的最佳工艺参数组合为:夹持V角33°,输送速度285 mm/s,切割转速1 250 r/min。选取去头预处理、腹部六节完整的对虾在带式对虾开背机上以最佳参数组合进行试验验证,试验结果为:切口长度成功率92.5%,切口对称度成功率90.83%,切口深度成功率90.0%,切口光滑度成功率93.3%,与预测值误差绝对值均小于5%。验证试验结果表明带式对虾开背机性能可靠稳定,各项指标均满足要求。

Design and experiment of shrimp backside cutting machine formed by belt clamping and conveying

Shrimp backside cutting is an important pretreatment process of shrimp's mechanized peeling, which directly affects the realization of mechanical shelling. Aiming at the current situation of immature development of shrimp cutting and the shortage of backside cutting device in China,it is urgent to develop the shrimp cutting machine which is suitable for Penaeus vannamei and adapted to each level shrimp with different shape parameters. Furthermore, to develop a practical and reliable shrimp cutting equipment is of great significance to promote shrimp's mechanized processing. In this paper, a shrimp backside cutting machine formed by belt clamping and conveying has been designed and manufactured. This machine consisted of four main sections: the clamping and conveying mechanism, the adjusting mechanism of clamping angle-V, the fine-tuning mechanism of blade height, and the depth limiting and guiding parts. The basic requirement for clamping and conveying mechanism was to achieve continuous and stable gripping of the shrimp and to ensure the correct posture when getting on the shrimp's backside cutting and reduce the clamped body damage of shrimp. The clamping and conveying mechanism consisted of two sets of independent belt conveyor mechanism. The inner side of the belt was arranged in rows of tensioning wheels which led the conveyor belt, and the entire conveyor belt was driven by a stepper motor with a timing pulley with transmission ratio. The clamping angle V adjustment motion was accomplished by the angle adjustment and the gap compensation. The angle adjustment electric push rod drives the slider to slide up and down soon afterwards the bending rocker arm begins rotating, and the action produced torque to drive the belt base turn a certain angle, and then to achieve the adjustment action of the clamping V angle which formed by the two symmetrical belt. The gap compensation electric push rod drove the base pin to move left and right and then adjust the gap between the two symmetrical belts drive mechanism, and these actions ensured the space in the bottom of the V-shaped clamping unchanged ultimately. The depth limiting plate and the inverted U-shaped plate were mounted on the motor shield. The disc knife passed through the slot of the depth limiting plate to control the depth of the incision by adjusting the height of the blade leaking. Inverted U-shaped plate with different closed mouth on the two sides which was arranged at a certain angle on the above of the V-shaped clamping space, and the plate forms an inverted U-shaped and wedge-shaped space that converged along the movement of the shrimp. The depth limiting and guiding parts can straighten and guide the shrimp body and effectively ensure the depth and incision symmetry. Through the single factor test, it was illustrated that how the three key parameters that the clamping V Angle, conveying speed and cutting speed, to influence four evaluation indicators which were incision length, incision symmetry, incision depth and incision smoothing on the shrimp backside cutting machine. Furthermore the three key parameters have been optimized. An orthogonal test of three factors and three levels which had been arranged by Box-Behnken Design, the regression mathematical models of four evaluation indicators with three key parameters had been found. The variance analysis of the test results was carried out by using Design-Expert8.06 software. The satisfactory process parameters of the shrimp backside cutting machine had been obtained through the optimization analysis. The optimal combination of the process parameters were as follows:conveying angel of 33°, conveying speed of 285 mm/s, cutting speed of 1250 r/min. From the results of predicting model, success rate of incision length was 92.46%, success rate of incision symmetry was 95%, success rate of incision depth was 91.83%, success rate of incision smoothing was 93.54%; The related verification experiment under the best combination of the process parameters was carried out, and the experimental results showed that the success rate of incision length was 92.5%, success rate of incision symmetry was 90.83%, success rate of incision depth was 90.0%, success rate of incision smoothing was 93.33%. By comparing the predicted results with experimental results, we concluded that the shrimp backside cutting machine can work reliably and stably under condition of the best parameter combination, and moreover all indicators can meet the requirements.