自動螺絲刀設計【快速擰緊 松出螺絲的的多功能手動螺絲刀】【說明書+PROE】
自動螺絲刀設計【快速擰緊 松出螺絲的的多功能手動螺絲刀】【說明書+PROE】,快速擰緊 松出螺絲的的多功能手動螺絲刀,說明書+PROE,自動螺絲刀設計【快速擰緊,松出螺絲的的多功能手動螺絲刀】【說明書+PROE】,自動,螺絲刀,設計,快速,擰緊,螺絲,多功能,手動,說明書,仿單
#include
#include
#define uchar unsigned char
#define uint unsigned int
//ads7825 P2為輸出數(shù)據(jù)
sbit CS=P1^0;
sbit RC=P1^1;
sbit BUSY=P1^2;
sbit BYTE=P1^3;
//電機
PWM=P1^4; //PWM輸出
En_m=P1^5; //電機的另一端
//定時器/PWM 先高電平再低電平
uchar T_Count=0; //當前計數(shù)值
uchar T_Number=0; //電平轉換點
uchar T_Sum=100; //電平最長時間
//正轉反轉按鍵
sbit ZF=P1^6; //低電平反轉，高電平正轉
//扭矩臨界值
uint NJ=0x8000;
void PWM_time() interrupt 1
{
TH0=0xff; //約129us定時
TL0=0x80;
T_Count++;
if(T_Count==T_Sum) //達到一個周期
T_Count=0;
else if(T_Count<=T_Number) //當計數(shù)小于電平轉換點，設置高電平
PWM=1;
else //計數(shù)大于電平轉換點，設置低電平
PWM=0;
}
Init_time()
{
TMOD=0x80; //定時器0 工作方式0
TH0=0xff; //約258us定時
TL0=0x80;
IE=0x82; //允許T0中斷
TR0=1;
}
Init_ads7825()
{
CS=0; //啟動ads7825
}
uint Read_ads7825()
{
uint num=0;
RC=1; //一個超過25us的低脈沖
_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();
RC=0;
_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();
_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();
_nop_();_nop_();_nop_();_nop_();_nop_();_nop_();
while(!BUSY); //忙等待
RC=1; //脈沖完畢
BYTE=1;
num=P2; //采集高8位
num<<=8;
BYTE=0
num=num|P2; //采集低8位
return num;
}
Contorl_M(uchar i,uchar j,) //控制電機 占空比 正反轉
{
En_m=j; //電機一端設置為低電平正轉 高電平反轉
T_Number=i; //PWM占空比i% 或者1-i%
T_Count=0; //PWM計數(shù)歸0
}
main()
{
Init_time();
Init_ads7825();
while(1)
{
while(ZF==1) //正轉 擰螺絲
{
Contorl_M(60,0); //占空比60
if(Read_ads7825()>NJ) //當?shù)竭_扭矩力，關閉電機
Contol_M(0;0);
}
while(ZF==0) //反轉 松螺絲
Control_M(30,1); //占空比70
}
}
否
反
正
啟動電動機反旋轉
正反轉按鍵
關閉電動機
是
電源開關打開
啟動電動機正旋轉
模數(shù)ADS7825測量扭矩
旋轉扭矩
大于一定值
一、市場調查研究：
螺絲是常見的一種工件，大到重型機械，小到日常生活用品，我們總能看到螺絲的身影。因此擰螺絲的螺絲刀在生活和生產中占有很重要的地位?，F(xiàn)在出現(xiàn)的比較多的螺絲刀有普通的手動螺絲刀和電動螺絲刀。普通手動螺絲刀結構簡單，價格低廉，但是效率比較低，特別是有較長的螺釘要擰時更明顯。電動螺絲刀效率高，且省時省力，適合大規(guī)模生產使用，且可以設計成帶電池的電動螺絲刀，從而可以抵消對電源線的依賴。
二、設計方案：
基于以上對市場現(xiàn)有螺絲刀的性能分析，設計一款電動螺絲刀。
1、設計要求：
能快速擰緊/松出螺絲的的多功能手動螺絲刀，其特征是：單手操作，可實現(xiàn)快速正反轉，也可變速為正常螺絲刀一樣工作；可更換多種規(guī)格的螺絲刀頭。
2、 結構設計 ：
本產品由高效變速裝置、多功能刀頭裝置和變速裝置組成。
1） 高效變速裝置 主要由手柄、螺絲刀架、固定在螺絲刀柄內的變速直齒輪組組成。工作時，操作手法和普通螺絲刀相近，握住手柄正反轉，簡單并排的變速直齒輪組能使螺絲刀桿直接正反旋轉。為了結構緊湊，設計的變速直齒輪組的傳動比為1：3.5 ，當用于快速擰緊/松開螺絲時，轉一圈手柄，可以使螺絲旋進/松開3.5圈，實現(xiàn)高效旋
高效變速裝置
2）多功能刀頭裝置 是便于拆裝更換螺絲刀頭的裝置，可以安裝不同規(guī)格的螺絲刀頭。
3）變速裝置 緊固螺釘需要較大力矩時，將變速裝置小推件拉到如圖中所示位置，則螺絲刀的傳動比為1比1，可以滿足擰緊要求，此時螺絲刀與普通螺絲刀無異。將變速小推件往右拉，則可實現(xiàn)1：3.5的高效旋轉。
作品整體效果圖如圖-4所示。
圖-2 多功能刀頭裝置
圖-3 變速裝置
圖-4 作品整體效果圖
3、螺絲刀控制部分設計：
本設計產品帶有自動停止控制功能，以下為該產品的控制模塊設計設計如下。
1) 硬件設計 如圖1。其主要由單片機、電機、開關電路、模數(shù)轉換、力傳感器等組成的。由單刀開關控制正反轉，來實現(xiàn)擰螺絲和松螺絲兩個動作。
當需要擰螺絲時，斷開開關S1，打開電源。單片機將控制模數(shù)轉換，把扭矩力電壓輸入到單片機，當扭矩力小于一定值時，電機正轉。當扭矩力達到一定值時，關閉電機。
當需要松螺絲時，閉合開關S1，打開電源。單片機將控制電機一直反轉，直到手動關閉電源。
圖1
2）程序流程設計
3）程序軟件設計
程序預定義 如圖3。預先定義了有單片機封裝庫，ADS7825模數(shù)轉換，電機，PWM，按鍵，扭矩力調節(jié)值。
圖3
主程序 如圖4。通電以后，首先初始化各個寄存器，調整各個寄存器工作狀態(tài)。然后讀取張反轉按鍵ZF的狀態(tài)。如果是正轉狀態(tài)，則控制電機以占空比60%正轉，直到達到一定扭矩力才會停下來。如果是反轉狀態(tài)，則控制電機以占空比70%反轉，直到手動關閉電源。
圖4
PWM定時器 如圖5.設置定時器T，定時129us中斷一次。以129us乘以100為一個PWM控制周期。在電平轉換點之前為高電平，之后為低電平。
圖5
寄存器初始化 如圖6。初始化定時器，啟動模數(shù)轉換。
圖6
讀取扭矩力 如圖7.單片機以一個超過25us的低脈沖對ADS7825的RC引腳進行操作，控制BYTE采集16位的扭矩力數(shù)據(jù)。
圖7
控制電機 如圖8。單片機控制定時器的電平轉換點來控制PWM的占空比和電機轉向。
圖8
三 創(chuàng)新點總結：
1、此電動螺絲刀可以使用電池操作，抵消了以前的電動螺絲刀對電源線的依賴；
2、其巧妙利用齒輪的變速傳動，轉動主動輪，帶動從動輪高倍轉動，使被擰螺釘快速擰緊/松開，大大提高了工作效率；
3、還可以快速變換不同規(guī)格的螺絲刀頭，適合對各種規(guī)格的螺絲操作。；
4、其體積小巧、結構緊湊、攜帶方便，操作時只需單手就可以完成，高空作業(yè)的操作人員無須雙手操作，大大提高了高空作業(yè)的安全系數(shù)；
5、結構簡單、造價低廉，適合大眾的需求。
四、應用前景：
現(xiàn)在市場上主要有普通手動螺絲刀和帶電源線的電動螺絲刀這兩種。普通手動螺絲刀擰螺釘時，受到手轉動角度的限制，其速度慢、效率低，工作消耗人的體力高，而且，當在高空仰頭工作時，人容易勞累；而電動螺絲刀的工作效率雖高，但由于其購買價格也高，且受到用電的限制，只能在有電源供應的地方使用，其體積較大，攜帶不方便。
高效變速螺絲刀克服了上面兩種螺絲刀的缺陷，其體積小巧，便于攜帶，工作時只需單手操作，傳動比可達1:3.5甚至可以設計更高的傳動比，工作方便快捷，省時省力，大大提高了工作效率；而且高效變速螺絲刀的生產流程相對簡單，價格比較便宜，更適合大眾需求。
附件：部分零件圖
心 得 體 會
1、從設計創(chuàng)意到完成作品的加工制作，我們經歷了資料的檢索、查詢、整理與分析，數(shù)據(jù)處理能力得到提升；方案的不斷修改與完善讓我們學會設計與加工要統(tǒng)籌兼顧；在機構設計與產品加工中我們將專業(yè)知識充分運用到了實際產品開發(fā)。在整個設計與制造過程中我們進一步掌握了機械設計與加工的步驟和要領，深刻體會到團隊協(xié)作的重要性，同時團隊成員綜合素質和動手能力得到了很大的提高。
2、本次制作充分將所掌握的課本知識融入其中，比如把《機械原理》，計算機編程語言知識運用到機構的設計中，運用《工程力學》、《金屬工藝學》和《數(shù)控加工技術》知識結合CAD、PROE軟件對零件進行了合理的選材和設計加工制造。
3、從早期的設計構思到作品加工完成，我們深刻認識到現(xiàn)實與理論往往有較大差距，理論設想需要得到實驗和實際產品的驗證，機械設計與制造是一個不斷循環(huán)反復完善的過程。通過參與作品制作，我們學到了不少實用知識，真正體會到實踐出真知的道理。
4、當我們耐心地解決一個又一個問題時，體會到機械設計是一項牽一發(fā)而動全身的工作。因此在加工制造之前考慮整體機構各方面因素的時候要非常嚴謹和務求全面，在追求功能的實現(xiàn)的同時，必須充分地考慮到實際加工的困難、產品的性價比等?？傊?，機械設計要“理論結合實際”。
螺絲刀控制系統(tǒng)
1、 硬件設計
如圖1。其主要由單片機、電機、開關電路、模數(shù)轉換、力傳感器等組成的。
由單刀開關控制正反轉，來實現(xiàn)擰螺絲和松螺絲兩個動作。
當需要擰螺絲時，斷開開關S1，打開電源。單片機將控制模數(shù)轉換，把扭矩力電壓輸入到單片機，當扭矩力小于一定值時，電機正轉。當扭矩力達到一定值時，關閉電機。
當需要松螺絲時，閉合開關S1，打開電源。單片機將控制電機一直反轉，直到手動關閉電源。
圖1
2、 程序流程設計
圖2
3、 程序軟件設計
程序預定義
如圖3。預先定義了有單片機封裝庫，ADS7825模數(shù)轉換，電機，PWM，按鍵，扭矩力調節(jié)值。
圖3
主程序
如圖4。通電以后，首先初始化各個寄存器，調整各個寄存器工作狀態(tài)。然后讀取張反轉按鍵ZF的狀態(tài)。如果是正轉狀態(tài)，則控制電機以占空比60%正轉，直到達到一定扭矩力才會停下來。如果是反轉狀態(tài)，則控制電機以占空比70%反轉，直到手動關閉電源。
圖4
PWM定時器
如圖5.設置定時器T，定時129us中斷一次。以129us乘以100為一個PWM控制周期。在電平轉換點之前為高電平，之后為低電平。
圖5
寄存器初始化
如圖6。初始化定時器，啟動模數(shù)轉換。
圖6
讀取扭矩力
如圖7.單片機以一個超過25us的低脈沖對ADS7825的RC引腳進行操作，控制BYTE采集16位的扭矩力數(shù)據(jù)。
圖7
控制電機
如圖8。單片機控制定時器的電平轉換點來控制PWM的占空比和電機轉向。
圖8
畢業(yè)設計（論文）外文翻譯
題目 鈦合金攻螺紋技術及絲錐改進
專 業(yè) 名 稱 機械設計制造及其自動化
班 級 學 號 078105235
學 生 姓 名 曾 威
指 導 教 師 王細洋
填 表 日 期 2011 年 3 月 12 日
鈦合金攻螺紋技術及絲錐改進
【摘要】鈦合金是一種比重小、強度高、耐腐蝕和耐熱等特性的金屬結構材料。鈦合金攻螺紋切削時刀具極易磨損，刀具壽命很短。通過對鈦合金攻螺紋過程受力分析，將絲錐直槽變?yōu)槁菪郏梢允骨邢鳠岷颓邢髁Σ恢劣谶^分集中于切削刃附近，改善散熱條件，也可加強切削刃，減少崩損。
【關鍵字】鈦合金、攻螺紋、金屬結構材料、熱處理強化、絲錐直槽、螺旋槽
鈦合金是一種比重小、強度高、耐腐蝕和耐熱等特性的金屬結構材料。TA7屬單相組織的型鈦合金，不能熱處理強化，通常在退火狀態(tài)下使用，具有良好的熱穩(wěn)定性和熱強性。TC4屬雙粗組織的型合金，有較高的力學性能和高溫變形能力，良好的韌性和塑性，能進行各種熱加工和熱處理強化。鈦合金在100~150仍有很高的強度，被廣泛應用于火箭發(fā)動機外殼、航空發(fā)動機氣機盤、葉片、結構鍛件等。
1.鈦合金攻螺紋切削過程特點
鈦合金是一種難切削材料，突出特點是刀具極易磨損，刀具壽命很短。主要體現(xiàn)在：
（1）切削層變形小由于鈦合金的塑性低和鈦的化學活潑性高，在高的切削溫度下化學親和性很強，容易與大氣中的氧、氮等元素化合，從而脆性降低，切削變形小。
（2）切削溫度高鈦合金導熱性很差，導熱系數(shù)只相當于45鋼的1/5~1/7切削熱不容易傳出，集中在切削區(qū)和切削刃附近較小范圍內。
（3）冷硬現(xiàn)象嚴重一是切削過程中產生的塑性變形，另一方面在高的切削溫度下，鈦很容易吸收空氣中的氧和氮形成硬而脆的外皮，冷硬現(xiàn)象不僅會降低零件的疲勞強度，而且能加劇刀具磨損程度。
（4）刀具容易磨損主要有機械磨損：毛坯余量和組織不均勻，硬皮與刀具表面接觸發(fā)生強烈的機械摩擦，使刀具受到不均勻的負荷造成崩刃現(xiàn)象。此外切削過程中已加工表面較大的彈性恢復，也使刀具磨損。粘接磨損：鈦合金對刀具材料的親和性很強，在切削溫度高和切削力大的條件下，很容易與刀具中的某些元素如C、Ti、Co等粘附在一起，隨切屑的流出帶走刀具材料中的質點。
2．鈦合金攻螺紋過程受力分析及改善措施
（1）切削層變化帶來的絲錐受力不均勻絲錐攻螺紋過程屬于半封閉式多刃薄切削過程，與車削螺紋相比較，切削條件惡劣。在工件底孔內切出的螺紋，是由絲錐切削刃瓣上的各切削牙逐層切削而成的。不難看出，絲錐或工件旋轉一周后，每個切削牙都前進一個螺距，并分別從工件上切除一層金屬。用機用絲錐攻螺紋時，隨著絲錐切入孔中，切削層總面積逐漸增加。當切削錐全部進入孔中工作時，切削層總面積達到最大值。當絲錐再繼續(xù)前進時，由于校準部不起切削作用，所以切削層總面積不再增加。對于鈦合金來說，因切削層巨大的摩擦力和塑性變形給運動中的絲錐受力帶來了波動。一個最有效的改變辦法是將螺紋孔底孔直徑增加到所允許的上限，最大程度地減小切削層厚度。
（2）“陷切”造成的絲錐受力惡化攻螺紋時，作用在絲錐各切削刃上的切削力可分解為軸向力、徑向力和切向力。切向力直接決定攻螺紋扭距的大小，其他兩個分力則影響攻螺紋的切削過程。從圖2中可以看出，開始攻螺紋時，絲錐依靠在工件上切出的JI螺紋側面被引導前進。但因JI面太小，加之鈦合金塑性變形，承受不了絲錐對工件的軸向力而產生接觸變形，使絲錐的軸向前進量不足，各刃瓣滯后并在螺紋表面一側切出階臺而造成“陷切”現(xiàn)象。攻螺紋繼續(xù)進行時，在由KJ、GH、GF、CD等側刃、頂刃切削時產生的軸向力合力Fa(-)和由JI、EF、AB等側刃切削時產生的軸向力合力Fa(+)未趨平衡以前，“陷切”現(xiàn)象將繼續(xù)發(fā)生。但隨著絲錐與工件相接觸的螺紋引導表面的增大，“陷切”量將逐漸減??；攻螺紋的“陷切”現(xiàn)象直接影響螺紋一側面的正確成形，并使其表面粗糙度值高，嚴重時足以啃住絲錐，使之處于抱死狀態(tài)。
（3）攻螺紋過程中的擺動容易使絲錐單向嵌入工件基體中在絲錐正常工作的條件下，如前所述，由于同時工作的絲錐各切削牙切削寬度不等，使前面切削牙的切削面積大于后面切削牙的切削面積，所以，作用在絲錐各刃瓣上的徑向力不等，也使徑向力的合力不等于零（）。顯然，在攻螺紋時，絲錐將偏向徑向力小的一邊，絲錐的軸線相對于孔的軸線將發(fā)生偏移，導致被加工的螺孔擴大同時也使絲錐緊貼在一邊。當絲錐的切削錐長度較短，即導角較大時，各刃瓣上切削牙的切削寬度差別愈大，中徑擴大的可能性越大，故絲錐的切削錐長度不宜太短。
（4）攻螺紋扭矩的非穩(wěn)定性攻螺紋的扭矩由三個部分組成，即切削扭矩、絲錐與已加工螺紋間的摩擦扭矩和由于切屑堵塞在容屑槽內產生的扭矩。在正常切削的條件下，攻螺紋扭矩主要是切削扭矩，后一種扭矩所占的比重一般很小，可忽略不計。絲錐在通孔中攻螺紋時扭矩的變化情況。隨著絲錐切入底孔，進行切削的牙數(shù)增加，攻螺紋扭矩增大。當切削錐全部進入底孔時，扭矩達到最大值。當絲錐的切削錐從孔的另一端露出時，攻螺紋扭矩開始減小。顯而易見，攻螺紋扭矩基本上與絲錐切削層總面積成正比，攻螺紋扭矩的變化規(guī)律與絲錐切削層總面積的變化規(guī)律大致相同。為了避免在扭矩最大值時用力過猛，必須掌握所施加扭矩大小及緩急程度。另外還可以通過以下途徑來有效地減小攻螺紋扭矩：1、增大前角使攻螺紋扭矩減小，例如前角為時，假設扭矩為100%，那么當前角變?yōu)闀r，則扭矩就減小到70%，前角時扭矩僅達到原來的53%，但是增大前角會使絲錐強度降低，也不利于散熱，這一點應注意。
一．選擇盡可能少的絲錐刃瓣數(shù)即槽數(shù)，這是因為槽數(shù)的增加，一方面使切削厚度變薄，難以切削，另一方面增加了絲錐與工件摩擦面積，使絲錐扭矩變大，一般的四槽比三槽約增加8%的扭矩。
二．選擇對口的切削液，減小摩擦。如濃度較大的硫化油，添加15%~20%的四氯化碳，可降低表面粗糙度值和減小絲錐咬死的可能性。
3．絲錐前面導向部分的導角既不能過大也不能太小，導角過大，切削層厚度大，受力容易崩牙咬死，切屑也不易卷曲，但導角過小，切屑過薄，在硬化層上摩擦，加劇絲錐磨損。另外絲錐校準部分不宜過長，否則和螺紋孔壁摩擦將會加劇，一般為4~5個螺距。
4．絲錐改進實例由于鈦合金材料在加工過程中容易產生表面加工硬化，特別是加工小直徑螺紋孔，成了難題。攻螺紋時由于縮孔，攻上幾扣，就抱住絲錐，切削力特別大，普通絲錐容易折斷，使工件無法繼續(xù)加工。基于上述受力分析過程，將絲錐的大徑、中徑、小徑磨小并分為四個等級，每只絲錐相差0.1mm，以期減少切削力帶來的影響，但是由于切削量小，工件又容易產生加工硬化，加工起來比較費勁，效率很低，攻上幾個螺紋孔就不能繼續(xù)使用了。后來我從改變切削的角度入手，經過多次反復實驗，將絲錐直槽變?yōu)槁菪郏丛谠邢餮郎习绰菪嵌饶ト?~2扣，以減小絲錐與切屑的接觸面積。前角由原來的減少至，使切屑與前刀面的接觸長度小，既可以增加切屑與前刀面的接觸面積，使切削熱和切削力不至于過分集中于切削刃附近，改善散熱條件，也可加強切削刃，減少崩損。
參考文獻:
[ 1] 高鐘锍.機電控制工程[M].北京:清華大學出版社,2002.
[2] 張建民.機電一體化系統(tǒng)設計[M].北京:北京理工大學出版社,2002.
[ 3] 王貴明.數(shù)控實用技術[M].北京:機械工業(yè)出版社,2000.
The alloy of titanium attacks whorl technology
and screwtap to improve
[Abstract] Titanium is of small specific gravity , high strength, strong corrosion resistance and heat resistance ,which are the characteristics of metallic structural materials. Titanium is a kind of material easily tapped cutting tool wear, shorting its using time . Titanium is tapping on stress analysis, tapping directly into the spiral groove that can make cutting heat and force without being unduly concentrated in the vicinity of the cutting edge ,not only improve heat dissipation, but also strengthen the cutting edge, in order to reduce losses collapse.
[Key word] Titanium, Gewinde scheiden, metal structural materials, heat resistance, Straight Fluted Taps, spiral chute
Titanium alloy is a kind of metal structural material , with characters of small proportion , high intensity, strong corrosion-resisting and heat-resisting and so on . TA7 belongs to the organized single-phase type of titanium alloy , which can't be strengthen under the heat treatment, used under the condition of putting out the fire in common situation , with good performence of hot stability and intensity . TC4 belongs to organized double-thick of type titanium alloy , which has higher mechanics performance and the ability of deformed under high temperature, good toughness and plasticity, which can work with all kinds of heat process and strengthen treatment. Titanium alloy still has very high intensity under. It is widely used in the outer shell of rocket engine, aviation engine chassis, blade, structural forging,etc..
1. The characteristics of the titanium alloy’s Gewinde scheiden whorl cut the process:
The titanium is a material which is very hard to cut. The outstanding characteristic is that the cutting tool is very easy to be polish and its life-span is very short . Main reflects are as following :
(1)Cut layer can transfigure small because Titanium alloy is plasticity lowness and the titanium chemistry is activity . Under the high temperature of cutting that have strong affine of chemistry and easy combination with element chemical such as oxygen , nitrogen easy to hit the target with atmosphere. It is brittleness lessening , cutting deformation are minor.
(2)Cut temperature high titanium alloy heat conductivity very bad, heat conduction coefficient whether 45 steel of 1/5~1/7s cut hot only, in smaller range near concentrating on the cutting area and cutting the edge.
(3)Cold hard phenomenon serious one cut out of shape plasticity that course produce, on the other hand at high cutting temperature, titanium very apt oxygen and nitrogen to absorb air form hard and fragile crust, the hard phenomenon of cold not only will reduce fatigue strength of the part but also can aggravate the cutter and wear and tear the intensity.
(4)The cutter is apt to wear and tear and mainly have machinery that is worn and torn: Blank surplus and organization even, hard skin with cutter surface exposed to, take place strong machinery rub, make the cutter caused and broken out the edge phenomenon by the load not even. Cut course process surface loud elasticity resume, make the cutter wear and tear too already. Sticking wears and tears: Titanium alloy affinity of material very strong to cutter, in cut temperature to be high cutting strength under the heavy terms, it is very easy to seize with some elements in the cutter such as C, Ti, Co,etc. together, with flowing out the particle taken away in the cutter material of smear metal.
2. Titanium alloy attacks the whorl course and is analyzed and improved the measure by strength.
(1)Cut layers of screwtap that change bring specialize in strength even screwtap whorl course belong to semi-closed many edge thin to cut the course, compared with whorl of turning, it is abominable to cut the condition. Whorl that cut out in work piece underport, to cut by screwtap edge every of petal cut tooth chase layers of cut, as shown in Fig. 1. It is easy to find out, after the screwtap or work piece rotates a circle, each one cuts the tooth and advances a pitch, and excise a layer of metal from work piece separately. Specialize in whorl, cut hole with machine with screwtap with screwtap, cut one layer of the whole area increase. When cutting all awls and entering and working in the hole, cut one layer of the whole area and reach the maximum. When the screwtap continues advancing again, do not play a cutting role because of the department of regulating, cut one layer of the whole area to no longer increase. To alloy of titanium, cut layers of enormous frictional force and plasticity deformation give screwtap of sport bring, fluctuate strength. A most effective change method increases underport diameters of hole of the whorl to the upper limit allowed, reduce and cut one layer of thickness to the greatest extent.
(2)" Fall into, cut " screwtap that cause worsen, specialize in whorl, act on in screwtap cutting strength cutting strength at the edge can resolve axial force, radial strength and tangential force into each ", as shown in Fig. 2. Tangential force determine, specialize in whorl size to sprain distance directly, other two component force influence cutting course to specialize in the whorl. Can find out begin specialize in whorl, JI that screwtap rely on at work piece cutting out lead, advance to the side of the whorl in 2 Fig.. But because JI too light, in addition titanium alloy plasticity out of shape, bear screwtap axial force in work piece produce, keep in touch out of shape, make the axial of the screwtap insufficient in advancing amount, every edge one lags behind and cuts out the steps platform and causes the " fall into and cut " phenomenon on one side of the surface of whorl. Specialize in whorl continue go on, by KJ, GH, GF, CD side edge, carry edge axial force that produce join forces cut, join forces Fa by JI, EF, axial force that AB produce when the side edge is cut '), trend towards before such as equilibrium, " fall into and cut " the phenomenon will continue taking place ". But the whorl contacted with the screwtap and work piece guides superficial increase, " fall into and cut " quantity will be reduced gradually "; Attack " falls into and cuts " the phenomenon influences the taking shape correctly of a side of whorl directly "ing of whorl, make surface its roughness enough to gnaw live in screwtap when being value serious high, make it in, embrace state extremely.
(3)Specialize in whorl swing of course apt to make screwtap to be one-way to imbed work piece of the matrices on terms that the screwtap work normally, as noted previously, because the screwtap working at the same time each cuts the tooth and cuts the width, make the cutting area of cutting the tooth above cut the cutting area of the tooth in the back of greater thanning, so, the radial strength of acting on screwtap every edge one makes the resultant of forces of radial strength not equal zero（）As shown in Fig. 3. Obviously, while attacking the whorl, screwtap agree more on radial to be strength little axis axis in hole of screwtap take place skew, cause, expand at the same time making screwtap stick to aside closely spiral shell hole that process. Cutting in screwtap awl length relatively short, lead when angle heavy, every edge cut cutting of tooth width difference loud at the petal, the bigger possibility China expanded directly, so the awl length of cutting of the screwtap should not be too short.
(4)That attacked torsion of whorl is not that the torsion that stability attacks the whorl is made up of three parts, cut torsion, screwtap with process friction torsion of whorl already and because smear metal stop up in torsion that bits produce in the trough of holding. Under the terms of cutting normally, it mainly cuts the torsion to attack the torsion of whorl, the last one proportion that torsion account for generally very light, can ignore. In Fig. 3 is the change of the torsion while attacking the whorl in the open hole of the screwtap. Cut underport with screwtap, tooth cut to go on count, increase, specialize in torsion of whorl increase. When cutting all awls and entering the underport, the torsion reaches the maximum. When the cutting awl of the screwtap emerges from another end of the hole, specializing in the torsion of whorl begins to reduce. Obviously, specialize in whorl torsion cut one layer of the whole area directly proportional to with screwtap basically, specialize in whorl change law and screwtap of torsion cut layers of change of the whole area law roughly same. In order to avoid exerting oneself in the torsion maximum too quicklily, must grasp the torsion size and pressing or otherwise intensity exerted. In addition it come, reduce, specialize in whorl torsion effectively through following route:
One. It is before it increase for horn make specialize in there aren't whorl the torsions,such as before horn, suppose torsion have 100%, angle turn into, torsion reduce get 70% then, the torsion only reaches original 53% when the the previous corner at present then, but the angle will make the screwtap intensity reduce before increasing, unfavorable to dispelling the heat, this should notice.
Two. choose screwtap edge petal that lack as much as possible count the trough is counted promptly, this is because the increase that the trough counted, make, cut thickness thin, difficult to cut, increase screwtaps and work piece rub the area on the other hand on one hand, make the torsion of screwtap large, four general troughs nearly increase 8% of the torsion than three troughs.
3 .Chooses the fitting cutting liquid, reduce the friction. Such as density heavy vulcanization oil, add 15%0% tetrachloromethane, can reduce surface roughness value and reduce possibility that screwtap kill.4~5, Whom screwtap lead partly lead angle can too little either, lead angle to be too big, cut layers of thickness heavy, strength being apt to break out tooth kill, the smear metal is difficult to be curly, but lead horn to be too light, smear metal too thin, rub on hardening layer, aggravate screwtap wear and tear. In addition the calibration part of the screwtap should not be too long, otherwise rub against whorl hole wall and aggravate, it is generally 4 pieces of pitch.
4.The screwtap improves the embodiment and is prone to the work hardening of surface in the course of processing because of the titanium alloy material, especially process the small diameter whorl hole, become the difficult problem. Specialize in whorl, because of contract hole, several deduct attack, embrace screwtap, cut strength to be very much heavy, the ordinary screwtap is easy to break, make the work piece unable to continue processing. Because of described above to receive strength analytic process, large foot-path, hit foot-path, path rub little dividing 4 grades into of screwtap, each screwtap differs by 0.1mm, in the hope of reducing and cutting the influence that strength brings, but because the cutting amount is small, the work piece is prone to the work hardening again, process and stand up more strenuous, efficiency is very low, attack, have several whorl hole can continue and use. Later on I start with changing the angle that is cut, through testing repeatedly many times, turn spiral trough into by frank trough screwtap, in cut tooth rub, go, 1 spike according to spiral angle originally, as shown in Fig. 5, in order to reduce the contact area of screwtaps and smear metal. The previous horn come from original reduction, make smear metal and one hundred sheetses of Taxi contact length little ago, already can increase smear metal and one hundred sheetses of Taxi contact area ago, make, cut hot cutting strength to be unlikely to concentrate on, cut edge while being excessive, improve the heat dissipation condition, can also strengthen and cut the edge, reduce and break out and decrease.
effect of the process parameters on the rim thickness of glass fiber and Wollastonite filled PBT by conventional and microcellular injection-molding process has been conducted.
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