研磨硬质合金拉丝模锥部的新方法

<正> 生产钢丝和钢绳大量使用模孔直径(dk)3～10毫米的硬算合金拉丝模。模孔的研磨量≥0.5～1.0毫米。磨孔各部分以工作带的研磨最费时。例如,由 dk=5毫米重磨至     

金刚石拉丝模的研磨与修复

介绍金刚石拉丝模组成结构、孔型特点 ;给出金刚石拉丝模国内外常用标准、拉拔不同金属用金刚石模的技术参数、我国金刚石模具的直径偏差及外形尺寸 ;对金刚石拉丝模的研磨修复时磨料的选用、研磨工艺的制定、常见缺陷产生原因及修复、孔型的测量等进行了阐述     

胎圈钢丝拉拔模具的修模质量改进

将需修复的拉丝模切开并测绘,利用Photoshop软件得到Φ4.27,3.50,1.75,1.38mm规格拉丝模的各部分尺寸和角度,发现修复后胎圈钢丝拉拔模具存在定径带不明显、工作锥角度不合理和偏心等问题。研究确定修模原则:定径带长度应根据拉拔材料、模具材料、润滑粉和拉拔工艺并通过试验确定;对应不同的道次压缩率选择工作锥角度。制定完善、系统、操作性强的磨模操作工艺,给出拉拔各道次模具孔型结构参数。采用新的磨模工艺修模后,模具平均吨钢丝损耗由0.16个降为0.09个。     

文摘

<正> 天然金刚石的修复程序:(1) 利用超声波研磨除去拉拔磨损,研磨入口锥角、拉拔角和出口锥角;(2) 抛光研磨表面;(3) 修复定径带并加以校准。多晶金刚石拉丝模修复通常是超声波研磨和抛光定径带。超声波研磨和抛光比较:成形—表面抛光;金刚     

制模技术前沿

据有关资料报道,目前发达国家拉丝模制造技术已进入新的发展阶段。为保证拉丝高速度,钢丝直径高精度,钢丝表面高光洁度,模具高寿命,磨模技术实现现代化,对磨模工艺进行了改进,其特点是：（１）利用计算机辅助设计,使孔型最优化;（２）磨模过程微机控制;（３）超声波抛光,保证模子表面光洁度;（４）采用激光衍射仪精确测量钢丝直径和椭圆度（特别对细丝）,绘制钢丝横截面图,并将信号反馈给研磨控制系统。制模技术前沿     

西德拉丝模制造技术分析

对西德拉丝模生产状况,拉丝模的技术参数、拉丝模加工设备特点、工艺性能及磨模工艺作了介绍。     

拉丝模的最佳孔型结构及加工方式

通过对英国MRB公司及自己制作的拉丝模的使用分析 ,认为直线型模孔是延长拉丝模寿命的关键因素 ,提出了实现直线型模孔孔型加工的 3个关键环节是直线式磨模设备、具备一套合理的操作性强的制模工艺和一套完善的加工手段。介绍直线型拉丝模的生产流程并举例说明。     

一种新型拉丝模芯卡具

<正> 1.问题的提出拉丝模是金属制品行业必不可少的专用工具。一般情况下各厂家均直接购进各种规格的成品模,经研磨加工后投入使用。但由于成品模价格较高,所需费用大(以我厂为例:按模耗量2块/吨计算,全军生产量0.8万吨需耗拉丝模1.6万块,每块平均价格按16元计,全年需人民币25.6万元)。所以很多厂家改为购进拉丝模芯自行镶装。这样虽     

硬质合金拉丝模的超声研磨

<正> 超声波加工钻石模很早就已在国内应用,但用在硬质合金拉丝模加工上目前为数不多,特别是较大孔径拉丝模更是如此。超声研磨是以频率为每秒钟2万周左右由电能转变为机械能的(2万次/秒左右作纵向运动)高速运动的加工设备。在加工钻石     

硬质合金模孔加工的新技术

加工钨钴硬质合金模一般使用圆锥形或菱形钢针以及磨粉 ,磨粉一般采用硬质材料或超硬质材料。磨模一般为针转动或拉丝模转动。磨模一般分为 3道工序 :粗磨、精磨、抛光。普通磨模工艺的缺点是 :(1 )生产效率低 (在 5～7ｍｉｎ内才能磨去 0 1ｍｍ) ;(2 )加工的几何尺寸准确度低。钢针常磨损过快 ,使模子内部分几何形状有缺陷 ,以致在精磨和抛光工序中也不易消除 ,从而不能满足用户要求。各国都在研究提高拉丝模磨针寿命的办法 ,在磨模钢针上附上钻石粉或聚晶钻石粉或其它种超硬质材料 ,再配合以各类加工方法。意大利丹尼利公司有一种振动磨…     

使用金刚石工具的石材加工设备的若干技术关键、设计原则及发展展望

金刚石工具广泛应用于石材开采、石材切割、石材抛磨、定厚、倒角磨边及异形石材加工等领域 .通过对磨头结构形式、磨石的排布等几类石材加工设备中技术关键的阐述 ,提出在采用金刚石工具的石材加工机械设计中应协调考虑金刚石工具磨料配方、进给速度、磨抛轨迹和冷却等因素的设计原则 ,并对该行业的发展前景进行了展望 .     

Effect of grind size and fat levels on the physico-chemical and sensory characteristics of low-fat ground buffalo meat patties

Two experiments were carried out to investigate the influence of grind size (3, 4 or 6 mm) and fat levels (6, 8, 10 or 20%) on the physico-chemical and sensory characteristics of low-fat ground buffalo meat patties prepared using a combination of carrageenan (0.5%) and sodium alginate (0.1%). At a constant fat level of nearly 8%, there was no significant difference (P>0.05) in the cooking yield, pH, proximate composition and dimensional changes of patties prepared at different grind sizes. However, shear force value increased significantly (P<0.05) with an increase in grind size. The sensory scores were significantly (P<0.05) higher for patties prepared using 3 mm grind size as compared to those prepared at 4 and 6 mm grind sizes and hence it was adopted as the optimum grind size for low-fat ground buffalo meat patties. At a constant grind size of 3mm, cooking yield, moisture, protein and gain in height were significantly (P<0.05) higher and shear force values were significantly (P<0.05) lower for patties at all low-fat levels as compared to the control with 20% fat. Based on its significantly higher (P<0.05) sensory scores, 10% fat level was selected as optimum for low-fat ground buffalo meat patties, although even at 8% fat level sensory rating remained between good to very good.     

不同处理番茄皮膳食纤维对体外发酵体系短链脂肪酸的影响

通过模拟人体肠道消化系统,对添加不同处理番茄皮膳食纤维(原料直接粉碎,原料超微粉碎,原料挤压膨化后超微粉碎)进行发酵后产生的短链脂肪酸进行测定,观察不同处理方式对体外发酵液中短链脂肪酸的影响。研究表明:三种不同处理方式均能显著(p<0.05)提高发酵液中乙酸、丙酸及异丁酸的含量,其中挤压膨化后超微粉碎效果较好,分别提高了157%,183%和43%;三种处理方式均能降低反应体系中丁酸及戊酸的含量,其中粗粉碎和挤压膨化后超微降低幅度最大,分别达20.4%和29.7%。三种处理方式对反应体系中异戊酸的产生无显著性差异(p>0.05)。     

超细气流粉碎技术在轻工业中的应用

近二十年来,随着对各种超细粉体材料需求量的快速增长,超细粉碎技术在现代高技术新材料产业中得到应用;气流粉碎技术作为超细粉碎的主要技术手段,在冶金、化工、轻工业、航天技术等领域已广泛应用,本文介绍了超细粉碎技术在部分轻工业中的应用。     

一种制粉机的结构设计及参数确定分析

该文介绍了一种碾搓式无粉尘制粉机的结构设计、工作原理、应用条件。还介绍了传动系统的参数确定及碾搓效果的分析     

Effects of corn grain endosperm type and fineness of grind on site of digestion,ruminal digestion kinetics,and flow of nitrogen fractions to the duodenum in lactating dairy cows

Our objective was to evaluate effects of corn grain endosperm type and fineness of grind on feed intake, feeding behavior, and productive performance of lactating cows. Eight ruminally and duodenally cannulated Holstein cows in mid lactation (130 ± 42 d in milk; mean ± standard deviation) were used in a duplicated 4 × 4 Latin square design with 21-d periods. A 2 × 2 factorial arrangement of treatments was used with main effects of corn grain endosperm type (floury or vitreous) and fineness of grind (fine or medium). Rations included alfalfa silage, corn treatments, protein supplement, minerals, and vitamins and were formulated to contain 29% starch, 27% neutral detergent fiber, 18.2% forage neutral detergent fiber, and 18% crude protein. Corn grain treatments supplied 86.2% of dietary starch. Endosperm was 25% vitreous for the floury treatment and 66% vitreous for the vitreous treatment. The floury treatment increased rate of starch degradation by 94% (19.2 vs. 9.9%/h) and decreased rate of starch passage by 38% (16.1 vs. 25.8%/h), increasing apparent ruminal starch digestibility by 117% (53.7 vs. 24.7%). The floury treatment increased total-tract starch digestibility by 8% (92.2 vs. 85.1%) despite 37% lower postruminal starch digestion for the floury treatment compared with vitreous corn (38.4 vs. 60.7% of starch intake). Fine grind size increased apparent ruminal starch digestibility by 52% (47.2 vs. 31.1%) compared with medium grind size by increasing the rate of starch degradation by 105% (19.5 vs. 9.5%/h) with no effect on rate of starch passage. However, total-tract starch digestibility was not affected by fineness of grind because postruminal starch digestibility was 37% greater for medium compared with fine grind size (57.2 vs. 41.9% of starch intake). Endosperm type did not affect flow of nitrogen (N) fractions to the duodenum or microbial N efficiency, whereas fine grind size increased duodenal flow of nonammonia N by increasing duodenal flow of microbial N by 22% compared with medium grind size (438 vs. 359 g/d) but did not affect apparent total-tract N digestibility. No interactions were detected for any measure of starch digestion, ruminal N metabolism, or flow of N fractions to the duodenum. Endosperm type greatly affected ruminal and total-tract starch digestibility independent of the fineness of grind of corn grain with no effects on flow of N fractions.     

油茶籽水浆发酵分层现象研究

为了探索将茶叶籽油生物发酵生产工艺引入到油茶籽油生产中的可能性,通过观察不同打浆轮次及处于不同发酵时间段的油茶籽水浆状态,深入研究了油茶籽水浆发酵分层现象的发生过程。结果表明:油茶籽水浆发酵开始时上下是浑然一体的,呈乳白色,随着发酵时间的延长,发酵液分层逐渐由模糊变为清晰,发酵进行到4 h左右,发酵液明显分为3层:乳白色上层、淡黄色中层及灰褐色下层;此后,各层逐渐变得坚实,到发酵16 h左右,发酵液各层厚度已经稳定,上层、中层及下层的相对厚度分别为16%、75%、9%。不同打浆轮次油茶籽水浆发酵液上层形成时间随着打浆轮次的增加逐渐推迟,发酵液上层相对厚度随着打浆轮次的增加而降低;前3轮水浆发酵液上层相对厚度之和占所有打浆轮次上层相对厚度总和的95.9%。油茶籽水浆发酵分层现象发生过程与结果与茶叶籽水浆基本相同,因此茶叶籽油生物发酵生产工艺完全可以用于油茶籽油生产。利用茶叶籽油生物发酵工艺生产油茶籽油时,只需打浆3轮就可以达到效益最大化。     

MIR-01型雪茄卷制机离线式茄衣茄套切刀磨刀机的研制

为解决MIR-01型雪茄卷制机茄衣茄套切刀磨损后无法快速磨削等问题,研制了一种离线式切刀磨刀机。磨刀机由砂轮高度调节机构、磨刀平台角度调节机构、砂轮传动机构三部分组成,通过精准调整砂轮高度和磨刀平台角度,使切刀与砂轮接触的角度保持一致;通过砂轮传动机构推动切刀完成刀刃的磨削过程,实现切刀分层定量磨削。取4把磨损严重的茄衣茄套切刀对磨刀机进行磨削测试,结果表明：经过两次磨削处理后,茄衣茄套切刀的使用时间分别增加43.35%和40.39%,提高了切刀磨削效率。该技术可为提升雪茄烟生产效率和产品品质提供支持。     

Effects of corn grain endosperm type and fineness of grind on feed intake,feeding behavior,and productive performance of lactating dairy cows

Our objective was to evaluate effects of corn grain endosperm type and fineness of grind on feed intake, feeding behavior, ruminal fermentation, and productive performance of lactating cows. Eight ruminally and duodenally cannulated Holstein cows in mid lactation (130 ± 42 d in milk; mean ± standard deviation) were used in a duplicated 4 × 4 Latin square design with 21-d periods. A 2 × 2 factorial arrangement of treatments was used with main effects of corn grain endosperm type (floury or vitreous) and fineness of grind of corn grain (fine or medium). Rations were formulated to contain 29% starch, 27% neutral detergent fiber, 18.2% forage neutral detergent fiber, and 18% crude protein. Corn grain treatments supplied 86.2% of dietary starch. Endosperm was 25% vitreous for floury corn and 66% vitreous for vitreous corn. Fineness of grind did not affect dry matter intake (DMI), but floury corn tended to reduce DMI (23.8 vs. 25.1 kg/d) compared with vitreous corn. Floury corn increased meal frequency more for fine grind size (9.57 vs. 9.41 meals/d) than medium grind size (9.78 vs. 9.75 meals/d). However, there were no effects of treatment on any other measure of feeding behavior. Endosperm type did not affect yields of milk or milk components or milk composition except that vitreous corn tended to decrease milk lactose concentration compared with floury corn. Finely ground corn decreased yields of milk (31.1 vs. 33.1 kg/d), 3.5% fat-corrected milk (33.1 vs. 35.1 kg/d), milk fat (1.22 vs. 1.32 kg/d), milk lactose (1.48 vs. 1.59 kg/d), and solids not fat (2.46 vs. 2.63 kg/d) compared with medium grind size. However, fineness of grind did not affect milk composition. Treatments had no effect on change in body weight or body condition score or efficiency of milk production (kg of 3.5% fat-corrected milk/kg of DMI). Mean ruminal pH was not affected by treatment, but pH variance was decreased by vitreous compared with floury corn. Total volatile fatty acids and propionate concentrations in the rumen were increased by floury compared with vitreous corn but were not affected by fineness of grind. Effects of fineness of grind on yield of milk and milk components were greater than the effects of corn grain vitreousness.