CK6140車床主軸傳動系統(tǒng)設(shè)計-主傳動設(shè)計

喜歡這套資料就充值下載吧。資源目錄里展示的都可在線預(yù)覽哦。下載后都有，請放心下載，文件全都包含在內(nèi)，圖紙為CAD格式可編輯，有疑問咨詢QQ:414951605 或 1304139763p 開發(fā)低成本接觸觸發(fā)探測器的數(shù)控車床 馬塞洛德爾戰(zhàn)爭a 雷吉納爾多·特謝拉·科埃略b a:工程圣卡洛斯 - 歐盟經(jīng)濟社會委員會，USP的冼星海大馬路工人Sancarlense400，CEP13566-590，圣保羅卡洛斯，SP，巴西的學(xué)校 b:工程圣卡洛斯 - 歐盟經(jīng)濟社會委員會，USP的冼星海大馬路工人Sancarlense400，CEP13566-590，圣保羅卡洛斯，SP，巴西的學(xué)校 2006年4月18日網(wǎng)上可查詢 摘要 數(shù)控機床使用觸發(fā)式測頭已成為世界標(biāo)準(zhǔn)，主要是由于減少了機器設(shè)置時間，以促進工件精度在機測量的能力。然而，一些障礙仍然需要調(diào)換，如測量程序編程困難，這些設(shè)備的成本高和技術(shù)文獻(xiàn)的數(shù)量較少有關(guān)此主題。這項工作提出的觸發(fā)式測頭對車間的應(yīng)用，討論時下用來產(chǎn)生觸發(fā)信號的技術(shù)審查。基于簡單的電接觸的新接觸觸發(fā)探頭模型被提出，與所需要的特性和成本低，要用于CNC車床。探針在實驗室開發(fā)的試驗示出0.003毫米（±3秒或99.73％置信區(qū)間）一個可重復(fù)性。這些特征似乎是非常媲美于工業(yè)車床應(yīng)用中最需要的。 關(guān)鍵詞： ·尺寸質(zhì)量監(jiān)測和控制; 接觸觸發(fā)探頭; ·在機測量系統(tǒng); ·CNC車床 簡介 如今，在制造系統(tǒng)發(fā)展最困難的挑戰(zhàn)是實現(xiàn)地區(qū)生產(chǎn)的全維管理，創(chuàng)建統(tǒng)計數(shù)據(jù)分析和部分到零件的控制。這種融合可以通過使用通常被稱為連接到數(shù)控機床觸發(fā)式測頭設(shè)備來達(dá)到。這些設(shè)備是用于基于項目的規(guī)格，閉環(huán)過程控制，部件的尺寸控制。制造，刀具補償，快速設(shè)置，過程的統(tǒng)計數(shù)據(jù)采集和更多的測量和校準(zhǔn)。 它是在目前的制造系統(tǒng)的發(fā)展趨勢非常重要的是要使用這些功能，使得可能部分對部分檢驗控制，如果必要的，這保證了尺寸誤差立即檢測，減少廢料，避免了一整批片都刮掉并降低成本，由于零件返工。 為了幫助維控上車削操作，這項工作開始引入觸發(fā)式探頭的特點，用于產(chǎn)生“觸發(fā)信號”技術(shù)。在此之后，本文提出了一種簡單和低成本的無線觸發(fā)式測頭的基礎(chǔ)上，直接電接觸的原則。原型是一起提交的重復(fù)性和準(zhǔn)確性的研究。 1. 觸發(fā)式測頭 第一個觸發(fā)式測頭的發(fā)明是為了解決一個具體的檢查要求，但繼續(xù)改造的設(shè)計和革命性的制造組件的過程后檢驗使用三坐標(biāo)測量機（CMM）的。在20世紀(jì)70年代末，幾乎所有主要的CMM制造商在世界上采用雷尼紹?探頭。 后來，由于數(shù)控進展，包括測量功能和直線光柵尺在其軸，使用這種裝置傳到機床，在那里他們成為了自動化生產(chǎn)系統(tǒng)，使得企業(yè)，從汽車到航空航天，提供精密零件的重要組成部分，減少廢料和最大限度地提高工作效率。 大衛(wèi)·麥克默特里開發(fā)的觸發(fā)式測頭技術(shù)在1972年的問題出現(xiàn)在勞斯萊斯公司，在那里他是引擎設(shè)計的副總。當(dāng)時，他正面臨著測量一些復(fù)雜的管路，只有毫米直徑6，對協(xié)和使用奧林巴斯引擎的問題。該管道必須適合精確扎實座架之間，但難度來衡量他們，一旦他們被制造。發(fā)現(xiàn)該溶液是觸發(fā)式探頭（TTP），它使用了一個簡單的原則，以確定探針和部件之間的接觸，以進行測量。 1973年，大衛(wèi)·麥克默特里注冊了一家名為雷尼紹早期成為計量和光譜解決方案的領(lǐng)先供應(yīng)商，制造商和研究人員在世界各地（雷尼紹[1]）。由于公司使用的專利機制，由打算加入這個市場上的其他公司需要開發(fā)其他技術(shù)。 3.觸發(fā)式測頭主要特點 獨立使用的技術(shù)，其原理是基于電信號此刻探頭的尖端接觸要測量的部分的產(chǎn)生（或中斷）。該信號，一般稱為觸發(fā)信號，被發(fā)送到把它轉(zhuǎn)換到由數(shù)控或CMM的被讀出的接口。在該機器接收到觸發(fā)信號的那一刻，它會立即凍結(jié)，并保存為計算和報告生成軸值（見圖例如1）。 圖.1.連接到數(shù)控機床的測量系統(tǒng)。 紅外線，無線電頻率或簡單的電線電纜：從TTP到探頭接口觸發(fā)信號傳輸可以采用三種基本不同的通信技術(shù)來建立。紅外通信用于標(biāo)準(zhǔn)車床和銑床傳統(tǒng)的應(yīng)用;這種技術(shù)提供了高可靠性，高傳輸速度率，低噪音干擾和低實施成本。這是接近萬無一失的系統(tǒng)，除非探頭和接收器都出視覺接觸的，作為探針深工件內(nèi)孔或其他凹陷內(nèi)時。對于這些情況和應(yīng)用中，射頻系統(tǒng)建議，（工具及制造[2]）。電線電纜通訊用于它們被安裝并固定在機床工作臺刀具調(diào)整器的探針。 4.探測循環(huán)和編程 據(jù)現(xiàn)代機加工在線[3]，少數(shù)專業(yè)人士會提出異議探測超速零件設(shè)置，設(shè)置刀具補償和執(zhí)行過程中的檢驗，至少在理論上的優(yōu)點。在實踐中，然而，探測器系統(tǒng)經(jīng)常被看作是難于使用和昂貴，購買。其結(jié)果是，他們已經(jīng)成為在高生產(chǎn)環(huán)境主要由有經(jīng)驗的程序員的工具。 為了使探測有效，更經(jīng)濟實惠的范圍廣泛的用戶，一些主要領(lǐng)導(dǎo)的CNC的制造商，如發(fā)那科，海德漢，大隈，辛辛那提米拉克龍公司和西門子，都包括在其數(shù)控軟件，專門開發(fā)的圖形用戶友好界面用于探測的Heidenhain TNC控制系列，例如，能夠自動地或手動地通過三維測量，使檢查的功能，如檢查孔的尺寸精度，確定飼料進行精加工，檢查工件的幾何形狀，并確定從公差偏差，確定工件前加工和掃描三維表面。另外，探測循環(huán)正在廣泛開發(fā)和可以由單個線的信息來激活（Zhou等人[4]）。 今天的標(biāo)準(zhǔn)機床提供精度和可重復(fù)性接近以前的水平僅在三坐標(biāo)測量機。此外，技術(shù)的進步使這些機器容易維護。測試和校準(zhǔn)技術(shù)，現(xiàn)已啟用的商店，以確保其機床的精度和健康。伸縮式球桿儀是由幾乎所有的商店很容易負(fù)擔(dān)得起的。一個藏書豐富的工具箱中也應(yīng)包含電子水平還是不錯的一套精密機床的水平。植物和大商店越來越多維護自己的激光干涉儀和電子水平，而租賃設(shè)備和診斷服務(wù)可購到各種來源的小商店（現(xiàn)代機加工在線[5]）。 另外，根據(jù)現(xiàn)代機加工在線[6]，CNC機器，在一般情況下，非常準(zhǔn)確，非常重復(fù)。他們媲美同等規(guī)模的三坐標(biāo)測量機的精度和可重復(fù)性。隨著在CNC檢查過程中的一些照顧，導(dǎo)致測量誤差和錯誤切割之間相互依存的因素可以被最小化。 5.技術(shù)用于生成所述觸發(fā)信號 根據(jù)沉和月亮[7]，有當(dāng)探針尖端接觸所述工件不產(chǎn)生觸發(fā)信號。探針將繼續(xù)走向和探頭尖端和工件之間的力會增加，??從而引起的物理量（例如，電阻），以達(dá)到一個閾值設(shè)置。當(dāng)物理的數(shù)量超過在感測系統(tǒng)中的閾限的觸發(fā)信號生成的。觸摸瞬間和觸發(fā)時刻之間的移動距離被稱為探針的預(yù)行程。主要是由彎曲筆軸的偏轉(zhuǎn)，它占大多數(shù)探針錯誤。 基本上有用于生成所述觸發(fā)信號四種不同的原則：電觸點（運動接觸），發(fā)光（激光干涉），變形（應(yīng)變計），并利用壓電效應(yīng)。 5.1運動接觸 目前，這是最常用的觸發(fā)式測頭廣泛。由大衛(wèi)·麥克默特里開發(fā)的，這個原理徹底改變了使用的坐標(biāo)測量機。 根據(jù)圖。 2，它是基于三個小的圓柱形件即保持就座于其他六個氣缸/球而引起的彈簧作用的壓力，限制其自由度直到觸針被帶到與該工件接觸的運動重新座位機構(gòu)。電流通常流經(jīng)三個席位串聯(lián)。當(dāng)探頭端部移動離開其穩(wěn)定位置，一個或多個座椅接觸場所及阻力的增加立即電子檢測（Mayer等人[8]和里德[9]）。測量完成后，當(dāng)探頭尖端移動從片背面，探頭彈簧迫使機構(gòu)回到初始穩(wěn)定位置，重新建立的標(biāo)準(zhǔn)電阻。 圖2.運動觸發(fā)式測頭的工作原理（模具和生產(chǎn)[2]）。 5.1.1系統(tǒng)優(yōu)勢 從由該系統(tǒng)提供的主要優(yōu)點，這是杰出的：該系統(tǒng)的簡單性，電氣 - 機械組件的堅固性，廣泛和研究原理。 5.1.2系統(tǒng)的缺點 由于電氣 - 機械裝配，運動探測器易受其電接點的消耗和腐蝕。 此外，這種探頭的主要典型特征是相關(guān)的預(yù)行程變化。因為觸針之前彎曲觸發(fā)是探針預(yù)行程的主要成分，該特性根據(jù)在觸摸方向的變化而變化（里德[10]）。這種行為發(fā)生由于這樣的事實，在三個“V型塊”由120°角隔開，內(nèi)部機構(gòu)的座位使所需要的力，以產(chǎn)生“觸發(fā)信號”，根據(jù)該接近的方向（以改變Kim和Chung [11 ]）。 Miguel等。 [12]也說，必要的動力，打開電接觸一個取決于即將到來的速度。 據(jù)沉和月亮[7]，同樣的觸發(fā)式測頭型號可能會表現(xiàn)出不同的預(yù)行程變化的行為，由于制造和組裝過程中的微小變化。 累積誤差使用觸筆更長大于30mm，由于這樣的事實，所必需的接觸力，生成“觸發(fā)信號”時發(fā)生彎曲的觸針和該偏轉(zhuǎn)正比于它的長度。 如果相對于其他系統(tǒng)，提供類似的好處，這些設(shè)備的購置成本是比較高的。該設(shè)備是眾所周知的，而他們生產(chǎn)的品牌有非常高的質(zhì)量有關(guān)。 5.2應(yīng)變計 應(yīng)變計用類比信息從產(chǎn)生在觸筆觸碰部的電阻變化導(dǎo)出探針交易，以進行測量。 使用這種技術(shù)作為數(shù)字交換機，它是必要的電的信號調(diào)節(jié)和處理，建立從其中的“觸發(fā)信號”時所產(chǎn)生的限制。 5.2.1優(yōu)勢 一個這種技術(shù)的主要優(yōu)點是，預(yù)行程變化比運動學(xué)探針因為觸針的變形本身負(fù)責(zé)trigging事件要低得多。由于這個原因，這種探針是非常準(zhǔn)確和使得有可能使用觸筆只要200毫米（圖3） 圖.3.預(yù)行程變化：比較運動探針（TP20）與應(yīng)變計探針（TP800）的性能（Renishaw的[1]）。探頭采用固體電子學(xué)，提供了長壽命和低磨損。根據(jù)模擬信號的校準(zhǔn)，這些系統(tǒng)能夠檢測0.2 N.接觸力 5.2.2缺點 與這些探頭有關(guān)的缺點依靠高收購成本，極其先進的電子設(shè)備，使得它非常微妙的設(shè)備和事實，也有極少數(shù)的文獻(xiàn)和信息專接近這些系統(tǒng)。 5.3激光 這些探頭操作使用光電開關(guān)的傳感器。透鏡系統(tǒng)匯聚LED發(fā)出的光束并聚焦在差動光電池上。當(dāng)觸針偏轉(zhuǎn)，差分光電管產(chǎn)生一個觸發(fā)信號，（約翰的Heidenhain博士[13]）。 5.3.1優(yōu)勢 如果與其他設(shè)備提供類似的性能之一的這些設(shè)備的主要優(yōu)點是與它的成本，相對低的。 5.3.2缺點 有對差分光電點所在的平行光發(fā)生，并產(chǎn)生了“觸發(fā)信號”，首先改變，針尖和被測定，將需要的部分之間的力偏轉(zhuǎn)的內(nèi)部機構(gòu)，類似于什么情況與有關(guān)到它的電觸點的開“運動探測”。由于這個原因，這兩個系統(tǒng)呈現(xiàn)類似預(yù)行程變化特性，表現(xiàn)出對方向的方法的準(zhǔn)確性依賴于部分進行測量和兩個系統(tǒng)都沒有指示要使用觸筆長于30毫米。 5.4壓電式傳感器 壓電探針基于用于該壓電晶體的兩個面之間產(chǎn)生，當(dāng)它被按下時的電勢差的原理。使用此物理原理，有可能設(shè)計出能夠產(chǎn)生從在探頭觸針到達(dá)部分的瞬間所產(chǎn)生的電位“觸發(fā)信號”探針。 5.4.1優(yōu)勢 他們是非常準(zhǔn)確和重復(fù)的系統(tǒng)。像應(yīng)變計探頭，預(yù)行程變化比運動學(xué)探針低得多，這是可能的校準(zhǔn)系統(tǒng)是敏感的力在0.2 N的順序 5.4.2缺點 他們可能是一些低頻噪聲的碰撞一樣敏感，啟動電機，主軸高加速/減速，機械振動等?；诤唵蔚碾娊佑|6.關(guān)于模型的這項工作的目的是利用基本的和眾所周知的技術(shù)，設(shè)計和制造成本低，堅固耐用和準(zhǔn)確的觸發(fā)式測頭能夠測量數(shù)控車床外徑。為此，精確的機械加工的零件和裝配的設(shè)計和應(yīng)用開發(fā)一種能夠在大觸發(fā)式探針的應(yīng)用中使用的系統(tǒng)。 6.1。該系統(tǒng) 所提出的設(shè)備的工作原理是由上閉觸筆（接地）和內(nèi)部目標(biāo)（正極）之間的電接觸。在這個特殊的時刻，“觸發(fā)信號”，并且由無線電（無線）發(fā)送到探頭的接口，就可以負(fù)責(zé)發(fā)送一個24伏的直流到CNC的適當(dāng)?shù)妮斎?。由于這樣的事實，該滑架將繼續(xù)由慣性后的“觸發(fā)信號”發(fā)生移動時，目標(biāo)應(yīng)該有一個缺點機制能夠吸附該移動，確保其表面完整性（圖4）。 圖.4在測量過程中的缺陷機制動態(tài)行為。 因此，開發(fā)了觸發(fā)式探頭的可重復(fù)性是直接與缺點系統(tǒng)觸發(fā)事件發(fā)生之后，精確座椅返回到其原始位置的能力有關(guān)。如果其缺點系統(tǒng)不能正常工作，會出現(xiàn)在測量和測定的下一個部分的直徑后探頭的長度的預(yù)置的變化將表現(xiàn)為比實際的不同。出于這個原因，其缺點系統(tǒng)的開發(fā)都非常小心，保證了系統(tǒng)良好的性能。探針被設(shè)計為在VDI刀柄使用的，根據(jù)DIN 69880和VDI 3425標(biāo)準(zhǔn)。 6.2。系統(tǒng)重復(fù)性和再現(xiàn)性（R＆R） 用于測試的觸發(fā)式測頭數(shù)控車床是一種INDEX-TRAUB，模型GU600，22千瓦的功率。數(shù)控系統(tǒng)是西門子810D，能夠提供實驗所需的測量功能。確定總系統(tǒng)的R＆R（探針+機床），實驗完成采取其一部分的直徑是預(yù)先加工和規(guī)范化。 在此之后，車削操作是使用硬質(zhì)合金刀具VBMT160404UC6010制成，切割0.010毫米從部件的直徑，采取一切必要的照顧與切削參數(shù)，以減少在過程中的工具磨損。 該器件然后檢查使用觸發(fā)式測頭的發(fā)展，連續(xù)探測60次在同一地點。還提供了手動測量是在使用普通的千分點。這些數(shù)據(jù)被保存在CNC和下載到PC。的轉(zhuǎn)動操作和連續(xù)測量步驟重復(fù)五次，從而獲得相對于直徑的每一個（圖5）的五個數(shù)據(jù)樣本。 圖.5例證的實驗過程的用于確定所述探針的R＆R和探針檢查部的照片。 7.結(jié)論 數(shù)控機床的使用觸發(fā)式測頭已成為一個世界性的必要性。然而，一些障礙仍然需要被轉(zhuǎn)置，像在測量例程編程困難，準(zhǔn)備技術(shù)員低數(shù)量和有關(guān)此主題的技術(shù)文獻(xiàn)和這些設(shè)備的高的購置成本。這個場景使用的中小型企業(yè)幾乎不可能，準(zhǔn)確地對他們來說，這對付小批量配套，其中過程控制容易超出范圍的工具。 這項工作是表示基于內(nèi)部交換機上的一個無線觸發(fā)式探頭模型，與所需要的特性和成本低，在數(shù)控車床中使用的開發(fā)的可行性。盡管探針簡單起見，在實驗室測試的結(jié)果顯示了0.003毫米（±3秒或99.73％置信區(qū)間）一個可重復(fù)性。這些特點是高兼容大部分用于工業(yè)車床應(yīng)用的需求。該探測器將繼續(xù)發(fā)展使得其在測量和改進其無線功能三個方向提供將采取。 Journal of Materials Processing Technology 179 (2006) 117123Development of a low cost Touch Trigger Probe for CNC LathesMarcelo Del Guerraa, Reginaldo Teixeira CoelhobaEscola de Engenharia de Sao Carlos-EESC-USP, Av. Trabalhador Sancarlense 400, CEP 13566-590, Sao Carlos, SP, BrazilbEscola de Engenharia de Sao Carlos-EESC-USP, Av. Trabalhador Sancarlense 400, CEP 13566-590, Sao Carlos, SP, BrazilAbstractThe use of Touch Trigger Probes for CNC Machine Tools has become a world standard, mainly due to the reduction of machine setup time andthe ability to promote workpiece accuracy on-machine measurements. However, some barriers still need to be transposed, like the measurementroutines programming difficulties, high costs of these equipments and the low number of technical literature about this subject. This work presentsa review on the applications of Touch Trigger Probes on shop floor, discussing nowadays technologies used to generate the trigger signal. Anew Touch Trigger Probe model based on a simple electrical contact is proposed, with the needed characteristics and low cost, to be used forCNC Lathes. The tests of the probe developed in the laboratory shown a repeatability of 0.003mm (3s or 99.73% confidence interval). Thosecharacteristics seem to be highly comparable to most needs for lathe applications in industries. 2006 Elsevier B.V. All rights reserved.Keywords: Dimensional quality monitoring and control; Touch Trigger Probes; On-machine measuring systems; CNC Lathes1. IntroductionOne of the, nowadays, most difficult challenges on manu-facturing system developments is to achieve total dimensionalcontrol of parts produced, creating statistical data analyses andpart-to-part control. This kind of integration may be reached byusing devices commonly called Touch Trigger Probes attachedtoCNCMachineTools.Theseequipmentsareusedformeasure-ments and calibrations based on projects specifications, closed-loopprocesscontrol,dimensionalcontrolofpartsmanufactured,toolcompensation,fastsetup,processstatisticaldataacquisitionand more.It is very important in current manufacturing systems trendstomaketheuseofthesefunctions,makingpossibleapart-to-partinspection control if necessary, which assures that dimensionalerrors are immediately detected, reducing scraps, avoiding thata full batch of pieces are scraped and reducing the costs due toparts reworks.Toassistdimensionalcontrolonturningoperations,thisworkstartsintroducingtheTouchTriggerProbescharacteristics,tech-nologies used to generate the “trigger signal”. After that, thispaper presents a simple and low cost wireless Touch TriggerCorresponding author.E-mail addresses: mdguerrasc.usp.br (M. Del Guerra),rtcoelhosc.usp.br (R.T. Coelho).Probe, based on a direct electrical contact principle. A proto-type is presented together with the repeatability and accuracystudies.2. Touch Trigger Probes earliesThe first Touch Trigger Probe was invented to solve a spe-cificinspectionrequirement,butwentontotransformthedesignand revolutionize the use of coordinate measuring machines(CMMs) for post-process inspection of manufactured compo-nents. In the end of 1970s, almost all the major CMM manufac-turers in the world were using RenishawsTMprobes.Later, due to CNC advances including measurement func-tions and linear encoder on its axes, the use of such devicesspread to machine tools, where they became a vital componenton automated production systems, allowing companies, fromautomotive to aerospace, to deliver precise components, reduc-ing scraps and maximizing productivity.David McMurtry developed the Touch Trigger Probes tech-nologyin1972.TheproblemaroseatRolls-Royceplc,wherehewas Assistant Chief of Engine Design. At that time, he was fac-ing the problem of measuring some complex pipe runs, of only6mmdiameter,fortheOlympusenginesusedonConcorde.Thepipeshadtofitaccuratelybetweensolidmountings,butthediffi-cultycameinmeasuringthemoncetheyhadbeenmanufactured.The solution found was the Touch Trigger Probe (TTP), whichusesasimpleprincipletoidentifythecontactbetweentheprobe0924-0136/$ see front matter 2006 Elsevier B.V. All rights reserved.doi:10.1016/j.jmatprotec.2006.03.093118M. Del Guerra, R.T. Coelho / Journal of Materials Processing Technology 179 (2006) 117123Fig. 1. A measurement system attached to a CNC Machine Tool.and the part to be measured. In 1973, David McMurtry regis-tered a company called Renishaw that early become the leadingprovider of metrology and spectroscopy solutions to manufac-turers and researchers around the world (Renishaw 1). Due tothe patented mechanism used by the company, other technolo-gies needed to be developed by other companies that intendedto join on this market.3. Touch Trigger Probes main characteristicsIndependently of the technology used, the principle is basedon the generation (or interruption) of an electrical signal at themoment the probes tip touches the part to be measured. Thissignal,generallycalledtriggersignal,issenttotheinterfacethatconverts it to be read by a CNC or a CMM. At the moment thatthe machine receives the trigger signal, it instantly freezes andsave the axis values for calculations and reports generation (seeexample in Fig. 1).The trigger signal transmission from the TTP to the probeinterface can be established using basically three different com-municationtechnologies:infrared,radiofrequenciesorasimplewire cable.Infraredcommunicationisusedforconventionalapplicationsfor standard lathes and milling machines; this technology pro-vides high reliability, high transmission speed rates, low noiseinterferences and low implementation costs. It is close to a fool-proof system, except when probe and receiver are out of visualcontact, as when the probe is deep within a bore or other depres-sion within the workpiece. For these cases and applications, aradiofrequencysystemisrecommended,(Tooling&Production2). Wire cable communication is used for tool setter probeswhich are mounted and fixed on the machine tables.4. Probing cycles and programmingAccordingtoModernMachineShopOnLine3,fewprofes-sionalswilldisputethemeritsofprobingforspeedingpartsetup,settingtooloffsetsandperformingin-processinspection,atleastin theory. In practice, however, probe systems often have beenviewed as difficult to use and expensive to buy. As a result, theyhave become tools used primarily by experienced programmersin high-production environments.To make probing effective and more affordable to a widerange of users, some of the main leading CNCs manufactures,such as Fanuc, Heidenhain, Okuma, Cincinnati Milacron andSiemens, are including, in its CNCs software, graphical user-friendly interfaces specially developed for probing. HeidenhainTNC control series, for example, are able to automatically ormanually carry through three-dimensional measurements andenables check functions, such as checking the dimensionalaccuracy of holes, determining feeds for finishing, checkingworkpiecegeometryandidentifyingdeviationsfromtolerances,identifyingworkpiecespriortomachiningandscanning3Dsur-faces. Also, probing cycles are being widely developed and canbe activated by a single line of information (Zhou et al. 4).Todaysstandardmachinetoolsdeliveraccuracyandrepeata-bility approaching levels formerly available only on CMMs. Inaddition,technologyadvancesaremakingthesemachineseasiertomaintain.Testandcalibrationtechnologyarenowavailabletoenable shops to ensure the accuracy and health of their machinetools. Telescoping ballbars are readily affordable by virtuallyanyshop.Awell-stockedtoolboxshouldalsocontaineitherelec-troniclevelsoragoodsetofprecisionmachinelevels.Plantsandlarge shops increasingly maintain their own laser interferome-tersandelectroniclevels,whilerentalequipmentanddiagnosticsservices are commercially available to small shops from varioussources (Modern Machine Shop On Line 5).Also, according to Modern Machine Shop On Line 6, CNCmachines are, in general, very accurate and extremely repeat-able. They compare favorably with the accuracy and repeata-bility of CMMs of similar size. With some care during theCNCinspectionprocess,thefactorsthatleadtointerdependencebetweenmeasurementerrorandcuttingerrorcanbeminimized.5. Technologies used to generate the trigger signalAccording to Shen and Moon 7, there is no trigger sig-nal generated when the probe tip touches the workpiece. Theprobe will continue to move toward and the force between theprobe tip and the workpiece will increase, causing a physicalquantity (e.g., resistance) to reach a threshold setting. A triggersignal is generated when the physical quantity exceeds a thresh-old limit in the sensing system. The travel distance betweenthe touch instant and the trigger instant is known as probe pre-travel. Mainly caused by bending deflection of the stylus shaft,it accounts for the majority of probe errors.Basically there are four different principles used to gener-ate the trigger signal: electrical contact (kinematic contact),light (laser interferometry), deformation (strain-gauges) and thepiezoelectric effect.5.1. Kinematic contactCurrently, this is the most used Touch Trigger Probewidespread. Developed by David McMurtry, this principle rev-olutionized the use of the coordinate measurement machines.According to Fig. 2, it is a kinematic re-seating mecha-nism based on three small cylindrical pieces that stay seatedon six other cylinders/spheres by the pressure caused by theM. Del Guerra, R.T. Coelho / Journal of Materials Processing Technology 179 (2006) 117123119Fig. 2. Kinematic Touch Trigger Probes working principle (Tooling & Produc-tion 2).spring action, restricting its degrees of freedom until the stylusis brought into contact with the workpiece. An electrical currentnormallyflowsthroughthethreeseatsinseries.Whentheprobetip moves away from its stable position, one or more of the seatcontacts breaks and the increase in resistance is immediatelydetected electronically (Mayer et al. 8 and Reid 9). After themeasurement is done, when the probe tip moves back from thepiece, the probe spring forces the mechanism back to the initialstable position, re-establishing the standard resistance.5.1.1. System advantagesFrom the main advantages presented by this system, it isdistinguished: the simplicity of the system, robustness of theelectro-mechanicalassembly,widespreadandstudiedprinciple.5.1.2. System disadvantagesDue to the electro-mechanical assembly, kinematic probesare susceptible to the consuming and corrosion of its electriccontacts.Besides, the main typical characteristic of this kind of probeis related to the pre-travel variation. Since stylus bending priorto trigger is the major constituent of probe pre-travel, this char-acteristic varies according to changes in touch directions (Reid10). This behavior happens due to the fact that the internalmechanismseatsinthree“V-Blocks”separatedbya120angle,causing the force necessary to generate the “trigger signal” tovary according to the approaching direction (Kim and Chung11).Miguel et al. 12 also say that the dynamic force necessaryto open one of the electric contacts depends on the approachingvelocity.AccordingtoShenandMoon7,sameTouchTriggerProbesmodels may show different pre-travel variation behavior due tomanufacture and small changes during the assembly process.Cumulative errors happen when using stylus longer than30mm due to the fact that the touching force necessary to gen-erate the “trigger signal” bends the stylus and this deflection isproportional to its length.The acquisition cost of these equipments is relatively highif compared to other systems that provide similar benefits. Thisequipment is very well known and the brand that manufacturesthem is associated with very high quality.5.2. Strain-gaugesStrain-gauges probes deals with analogical informationderiving from the electrical resistance variation produced whenthe stylus touch the part to be measured.To use this technique as a digital switch, it is necessary anelectrical signal conditioning and treatment, establishing thelimits from which the “trigger signal” is generated.5.2.1. AdvantagesOne of the main advantages of this technique is that thepre-travel variation is much lower than on kinematic probesbecause the stylus deformation itself is responsible for triggingthe event. For this reason, this kind of probe is extremely accu-rate and makes possible the use of stylus as long as 200mm(Fig. 3).Theprobeusessolidstateelectronics,providinglonglifeandlow wear. Based on analog signal calibration, these systems areable to detect contact forces of 0.2N.5.2.2. DisadvantagesThe disadvantages associated with these probes rely on thehighacquisitioncost,extremelyadvancedelectronicsthatmakesitverydelicateequipmentandthefactthatthereareveryfewlit-erature and information specifically approaching these systems.5.3. LaserThese probes operate with an optical switch as sensor. A lenssystem collimates the light generated from an LED and focusesit onto a differential photocell. When the stylus is deflected, thedifferential photocell produces a trigger signal, (Dr. JohannesHeidenhain 13).5.3.1. AdvantagesOne of the main advantages of these equipments is relatedto its cost, relatively low if compared to other equipments thatprovide similar performance.5.3.2. DisadvantagesTo have a change on the differential photocell point wherethe collimated light happens and generates the “trigger signal”,first of all, a force between the stylus tip and the part to bemeasuredwillbeneededtodeflecttheinternalmechanism,sim-ilarly to what happens with “kinematic probes” regarding tothe opening of its electrical contacts. For this reason, both sys-temspresentsimilarpre-travelvariationcharacteristics,showing120M. Del Guerra, R.T. Coelho / Journal of Materials Processing Technology 179 (2006) 117123Fig. 3. Pr e-travel variation: comparing the performance of kinematic probes (TP20) with strain-gauge probes (TP800) (Renishaw 1).accuracydependenceondirectionapproachtotheparttobemea-sured and both systems are not indicate to use stylus longer than30mm.5.4. Piezoelectric sensorPiezoelectric probes are based on the principle for which anelectric potential difference is generated between the two facesof a piezoelectric crystal when it is pressed. Using this physicalprinciple, it was possible to design a probe able to generatethe “trigger signal” from the electric potential generated at themoment the probe stylus reaches the part.5.4.1. AdvantagesThey are extremely accurate and repetitive systems. Likestrain-gauge probes, pre-travel variation is much lower than onkinematic probes and it is possible to calibrate the system to besensitive to forces in the order of 0.2N.5.4.2. DisadvantagesTheymaybesensitivetosomelowfrequencynoiseslikecol-lisions,startofmotors,highspindleaccelerations/decelerations,machine vibration, etc.6. Proposal of a model based on a simple electric contactThis work aims to use basic and well-known technologiesto design and manufacture a low cost, robust and accurateTouchTriggerProbeabletomeasureexternaldiametersonCNCLathes. For that, precise mechanical machined parts and assem-bly were designed and applied to develop a system able to beused on the major Touch Trigger Probes applications.6.1. The systemTheworkingprincipleoftheproposedequipmentconsistsonclosing an electrical contact between the stylus (grounded) andtheinternaltarget(PositivePole).Atthisparticularmoment,the“trigger signal” is generated and sent by radio (wireless) to theprobes interface that will be responsible for sending a 24V dcto an appropriate input of the CNC.Due to the fact that the carriage will continue to move byinertia after the “trigger signal” happens, the target should havea drawback mechanism able to adsorb this movement, assuringits surface integrity (Fig. 4).Consequently, the repeatability of the developed Touch Trig-ger Probe is directly associated with the ability of the drawbacksystem to precisely seats back to its original position after atrigger event occurs. If the drawback system does not workproperly, there will be a change on the probes length presetafter a measurement and the diameter of the next part measuredwill be showed as different than the real. For this reason, thedevelopment of the drawback system was done very carefullyto guarantee a good performance for the system.The probe was designed to be used on VDI Toolholders,according to DIN 69880 and VDI 3425 standards.6.2. System repeatability and reproducibility (R&R)The CNC Lathe used to test the Touch Trigger Probe was anINDEX-TRAUB, model GU600, 22kW power. The CNC wasFig. 4. Dynamic behavior of the drawback mechanism during the measurementprocess.M. Del Guerra, R.T. Coelho / Journal of Materials Processing Technology 179 (2006) 117123121Fig. 5. Illustration of the experiment procedure used to determine the probe R&R and a photo of the probe inspecting the part.a Siemens 810D, able to provide the measurement functionsneeded for the experiment.To determine the total system R&R (probe+machine tool),the experiment was accomplished taking a part of which diam-eter was previously machined and normalized.After that, a turning operation was made using a carbide cut-tingtoolVBMT160404UC6010,cutting0.010mmfromthepartdiameter, taking all the necessary care with the cutting parame-ters to reduce the tool wear during the process.The part was then inspected using the Touch Trigger Probedeveloped, probing 60 consecutive times at the same point.Also a manual measurement was made at that point usinga regular micrometer. The data were saved on the CNC anddownloaded to a PC. The turning operation and consecu-tive measurements procedure was repeated five times, obtain-ing five data samples relative to each one of the diameters(Fig. 5).According to QS9000 14, one of the most effective meth-odstostatisticallyanalyzeprocessandequipmentsisthemethodfor computing the repeatability and reproducibility (R&R). Therange and average method to calculate R&R computes thetotal measurement system variability, and allows the total mea-surement system variability to be separated into repeatability,reproducibility and part variation. The repeatability of the mea-surementsystemmaybeestimatedfromtheaverageofthemeanscollectedbythesameoperator,whilethereproducibilitymaybeestimated from the range of variation of the average results col-lected by different operators.Table 1Probe data collect to simulate the effect of three operators measuring five different partsOP1Diameter 1Diameter 2Diameter 3Diameter 4Diameter 5Measurement 139.3316239.3254539.3133439.3067239.29861Measurement 239.3316239.3251739.3133439.3074439.29783Measurement 339.3316239.3257439.3135739.3070739.29744Measurement 439.3312939.3251739.3144339.3063839.29783Measurement 539.3312939.324939.3144339.3060539.29744R0.0003320.000840.0010940.0013870.001171x/39.3314839.3252939.3138239.3067339.29783OP2Diameter 1Diameter 2Diameter 3Diameter 4Diameter 5Measurement 139.3312939.3254539.3133439.3067239.29744Measurement 239.3312939.3257439.3137939.3074439.2982Measurement 339.3312939.3257439.3133439.3074439.29861Measurement 439.3319539.3257439.31439.3078339.2982Measurement 539.3312939.324939.3133439.3074439.29861R0.0006640.000840.0006640.0011130.001171x/39.3314239.3255139.3135639.3073739.29821OP3Diameter 1Diameter 2Diameter 3Diameter 4Diameter 5Measurement 139.3316239.3257439.3133439.3067239.2982Measurement 239.3312939.3254539.3137939.3070739.29744Measurement 339.3325639.3260539.3133439.3067239.2982Measurement 439.3312939.324939.3133439.3063839.299Measurement 539.3312939.3251739.3133439.3067239.29783R0.001270.011530.0004490.0006830.001562x/39.3316139.3254639.3134339.3067239.29813122M. Del Guerra, R.T. Coelho / Journal of Materials Processing Technology 179 (2006) 117123Tosimulatetheeffectofdifferentoperators,themeasurementroutine was taken 3 consecutive times for each diameter (3 dataset containing 60 measurements each were generated for eachdiameter).OP1 (Operator 1) represents the first data set containing 60measurementstookfor