Drag Finishing of Delicate Parts

For complex parts with high surface finish specs, production deburring and surface prep can be done using the drag finishing process whereby the parts to be deburred and finished are mechanically dragged through the media while attached to fixtures—thus preventing the parts from contacting one another.


Drag finishing is a specialized version of mass or vibratory finishing—different in that the parts to be deburred and finished are mechanically dragged through the media while attached to fixtures—thus preventing the parts from contacting one another.
Mechanical surface finishing, also known as mass finishing or vibratory finishing, is a technology that has been around for more than six decades. Its applications range from burr removal, putting a radius on sharp edges, and degreasing and de-rusting/de-scaling of metal parts, all the way to high-gloss polishing of metal components. Mechanical finishing is generally associated with vibratory tumblers, centrifugal barrels or centrifugal disk machines.


Usually, such finishing systems consist of a work bowl filled with a mix of grinding or polishing media and the parts that need to be finished. By way of vibration or centrifugal force, the mass of media and parts is put into motion. The constant rubbing of media on parts over a certain period of time—from a few minutes to several hours—produces the desired surface finish.
In recent years, drag finishing has become a popular alternative for surface finishing of high-value and somewhat delicate metal components. Like pushing a plow through the soil and, thus, polishing its blade, in drag finishing systems, parts mounted to a carousel equipped with multiple workstations are dragged through a circular work bowl filled with grinding or polishing media.
Pressure and Speed
Mass finishing is all about pressure and speed. The higher the pressure exerted by the media on the parts, and the faster the media rubs on the parts, the faster the desired finishing results can be achieved. In this respect, drag finishing stands out over other finishing methods: Because of the high speed at which the parts are dragged through the media and the high pressure generated, drag finishing works 40 times faster than vibratory systems and about four to five times faster than high energy systems. High speed and pressure make drag finishing an optimum method, especially when it comes to parts made from hard-to-machine metals like high-alloy steel (stainless, titanium, Inconel, and so on), tool steel or parts with a high surface hardness.
No Part-on-Part Contact
The most outstanding characteristic of drag finishing is that parts are individually mounted onto workstations of the carousel. Depending on machine size, a carousel is usually equipped with four to 12 workstations, with each workstation loaded with one or multiple parts.
Compared with conventional mass finishing systems where the parts are free-floating in the media, in drag finishing systems, the parts—being individually attached to the workstations—never touch during the finishing process, thereby preventing part-on-part contact and any nicking or marring of the finish.
Individually mounting requires special part fixtures, which can sometimes pose an engineering challenge. But the payoff is worth the effort.
Aggressive Deburring to High-Gloss Polish
Applications for drag finishing range from aggressive deburring and edge breaking all the way to high gloss polish. A few examples of successful drag finishing applications include:
•Grinding and polishing of stainless steel boat propellers: These castings undergo a drag grinding process in one machine followed by a polishing step in a second drag finisher.
•Paint preparation of outboard marine drive components: These die castings require the removal of heat checks, breaking of sharp edges and a homogeneous surface finish prior to painting.
•Surface smoothing and polishing of turbine blades after machining and shot peening: This application reduces the surface roughness from Ra = 70 to Ra < 10 (1.8 micrometers to < 0.25 micrometers).
•Grinding and polishing of medical implants such as artificial knees, hip stems, ankles, and so on: After casting, these parts are machined and then undergo a multi-stage drag finishing process for aggressive surface grinding, surface smoothing and high-gloss polishing.

Consistent, Economical
Drag finishing is not an inexpensive surface finishing technology, but the technical and economic rewards can far outweigh the cost.
These systems frequently replace manual deburring/grinding operations. Manual deburring/grinding is highly labor intensive, and it is difficult to find operators willing to perform this physically demanding and extremely noisy and dirty work. Above all, the quality of manual grinding depends entirely on the people doing the work and their physical and mental condition. For this reason, manual deburring/grinding usually produces a significant amount of rework or even scrap.
On the other hand, once a drag finishing process is locked in, it consistently produces the same high finish quality day-in and day-out. With automation, the human factor can be totally neutralized and srap/rework can be reduced to practically zero from sometimes double digit percentages.
In mass finishing systems, regardless of part shape, the grinding or polishing media totally envelop parts to be finished, reaching all surface areas. Naturally, this also applies to drag finishing. Especially in the medical implant industry, drag finishing systems have increasingly displaced robotic grinding and buffing systems, which are limited when it comes to reaching certain surface areas of parts with a complex geometry.

Drag finishing systems are usually designed around the customer requirements, so a range of types and sizes of equipment is available. Of crucial importance are the size and quantity of parts that need to be finished. Generally, the rule-of-thumb “the bigger the part, the bigger the machine” must be applied. Of course, quantity also plays a big role. But just-in-time batch quantities may dictate small, multiple units instead of one large drag finisher.
At one extreme, there are “mini drag” systems on the market with as many as four workstations and a bowl diameter of 40 to 50 inches. At the other, “maxi drag” systems may have ten to 12 workstations and a bowl diameter of more than 180 inches.
Fixturing of parts to the workstations is of crucial importance, so they are always custom designed per application. Close communication between the customer and designer ensures that aspects such as degree of automation, wear protection, masking of certain areas, and so on are taken into consideration.
Whenever a manufacturer produces high value parts with a complex geometry, and these parts require a first-class surface finish (be it strictly functional or decorative), drag finishing is a surface finishing technology worth considering.

歡迎來到利豐行的世界,首先恭喜您來到這接受新的資訊讓產業更有競爭力,我們是提供精密表面處理的代理商,應對廠商高品質的表面處理需求,我們可以協助廠商滿足您對產業的不同要求,我們有能力達到非常卓越的表面處理品質,這是現有相關技術無法比擬的,表面處理技術皆集中於精密研磨,拋光VTD PVD工具鍍膜光學鍍膜 optical coating, 金屬濺鍍metallization, absolute chemie 精密CVD/PVD退鍍工藝EMAG Precision Electrochemical Machining 精密電化學加工技術(ECM / PECM)取代放電加工)EMAG 硬車削/乾式車削 hard turning, Koepfer 滾齒(齒輪加工製造技術, Reinecker, KARSTENS 內外圓研磨外圓+內圓曲面磨削, Naxos-Union軸研磨凸輪軸, KOPP非圓研磨, SW中心加工機, EMAG 雷射焊接自動化設備. oelheld 超高性能研磨切削油/EDM 放電加工液等我們成功的滿足了各行各業的要求,包括:精密需求高的軸承盒、射出成型的模具、高壓空氣閥、航太零配件、超高硬度的切削刀具、醫療配件及汽車用精密五金等等。我們的產品涵蓋了從桌上型到工業級的生產設備;從微細零配件到大型五金配件;從小型生產到大型量產;從半自動到全自動整合;我們的技術可提供您連續生產的效能,我們整體的服務及卓越的技術,恭迎您親自體驗.

OTEC公司專門研發製造金屬和非金屬的精密表面處理技術及設備,如:切削刀具的鎢鋼和高速鋼之表面處理,並廣泛為世界級大廠所採用如:Guhring oHGIskar等等。利豐行引進最先進的精密研磨和拋光技術,並希望提供台灣廠商提昇產業競爭力及生產效益和使用壽命。OTEC精密表面處理技術被認定為世界的領導者之一。研磨拋光、邊緣導角、功能性、裝飾性,這些精密表面處理技術除了令人讚嘆外,OTEC的技術整合還考量到生產者的需求,讓生產者在質量上和效益上及成本上有一個完美的平衡。機械操作除了更人性化還能額外整合生產者目前的製造設備。OTEC的產品兼具美觀及實耐用,不佔空間卻能在最小的單位中創造出最大的質量,當你採購了OTEC的設備後,除了擁有出眾的表面處理技術讓您的競爭力提升外,當客戶拜訪您公司時也不免對您令眼相看而發出讚嘆,OTEC是您生意的好伙伴。

VTD為德國真空鍍膜技術的佼佼者,其前身為東德的研究機構,技術開發人員就有二千多位,近來更是提供歐盟在太空貓頭鷹計畫中領先的真空光學鍍膜技術,而畫下鍍膜技術新世紀的里程碑,相信其在真空鍍膜的領域上,能為您帶來更有效益的生產方式及品質。 VTD開發比類鑽膜 DLC更硬更優越的SUPER HARD CARBON FILMS – DIAMOR®http://www.li-fung.biz/VTD_NEWS7.html


另外有EMAG ECM GmbH (ECM/PECM /uECM精微電化學加工技術在未來各種細微加工應用中佔有極大的優勢。該技術之優點係在於其加工能力與材料硬度無關,且能加工出微細及形狀複雜之表面結構,經由該製程加工後之產品表面具有粗糙度佳、無殘留應力及無裂縫產生等優良特性,常應用於航太、光電半導體、醫療器材、綠色能源、模具等產業上,本次研討會中特別邀請國內外知名學者及專家,介紹於精微電化學領域內之各種加工技術,可應用於燃料電池雙極板、生物晶片、微流體動壓軸承、微噴嘴、次世次流體分配閥元件、模具等產品加工上,機會難得,精彩可期。PECM為精密電化學切削的工程公司,其領先的技術,已在精密電化學切削領域達到量產化的水準。供顧客PECM精密電化學切削生產技術和客制化的製程設備。Electrochemical machining / pulse electrochemical machining / precise electrochemical machining. Electro chemical machining (ECM) is a method of removing metal by an electrochemicalprocess. It is used for working extremely hard materials or materials ...micro electrochemical machining


作為德國知名企業,埃馬克(EMAG)集團在齒輪、輪轂、轉向節等盤類零件加工方面一直不斷追求創新、高效,其倒置式車削中心不僅全球獨一無二,而且其在以車代磨工藝方面的研究和造詣也是首屈一指,其中EMAG VL3VL5 VSC 系列在連續切削和斷續切削方面都可以實現以車代磨,得到了國內外眾多客戶的普遍認可和廣泛使用。埃馬克(EMAG)車削中心VL 系列和VSC 系列作為埃馬克以車代磨技術的優秀代表,可加工直徑小于400m的各種盤類零件,不僅具有出色的表面加工質量、光潔度高,而且加工效率更勝一籌,速度非常快,且自動化程度也遠遠高于其他廠商的同類機床。而所有這些特質的誕生均來源于埃馬克諸多領先于行業一步的優秀技術和機床設計成果。 (1)採用人造大理石床身設計,減震性能和熱穩定性都非常好。埃馬克VL 系列和VSC 系列採用了高級礦物料澆鑄而成的車身,與灰鑄鐵床身相比,減震效果高出6-8 倍,床身靜動態平衡卓越,熱穩定性能出色,與傳統材料的床身相比,產品的表面光潔度好,刀具壽命更長。機床採用橋式框架結構,高架滑台安裝在床身上方並承載著立式主軸,所以受力非常均勻,剛性極佳。兩個回路的致冷機組可使機床溫度與環境溫度保持十分接近,從而消除了因溫度波動而引起的精度誤差。 (2)採用倒立式的機床設計,排屑非常方便,而且機床的導軌、光柵尺、主軸電機、帶套筒的主軸、刀塔、電器櫃等重要部件都在工作區的上方,落屑朝下,不會受到鐵屑的影響,因而對刀具壽命的提高及產品表面光潔度和幾何尺寸都非常有幫助。(3)機床配置了自動上下料系統,減少了人工操作的強度和誤差,減少了投資成本。(4)機床的主軸功率和扭矩都非常大,因此該機床既能做粗加工,也能做精加工,既可以硬車,也能做軟車,且都能滿足高精度、高表面質量的要求。用戶之前選用磨床對圖示零件進行加工。當得知EMAG VL5 機床以車代磨工藝後通過比較設備投資、日常生產消耗、加工效率等多方因素簽,用戶最終選擇了EMAG VL5結果不僅達到預期的表面加工質量要求,內孔直徑公差達到Cmk1.67 以上。而且提高加工效率一倍多,極大的降低了工件成本。EMAG 埃馬克VLVSC 系列加工的齒輪內孔不僅尺寸精度高表面光潔同時節約一半以上的投資成本。


利豐行著重於表面處理之前後製程技術,提供客戶individual & total finishing solutions 的整合作業,協助產業提升效能並降低成本。


利豐行事業有限公司 www.li-fung.biz 407台灣省台中市工業區3621
電話:+886 (04) 2355-2327傳真:+886 (04) 2355-2457


LI FUNG BUSINESS CO., LTD. www.li-fung.biz 407 1F No.2. 36th Rd., industry Park, Taichung City, Taiwan, R.O.C


本館專門提供 OTEC 表面處理技術皆集中於精密研磨,拋光, deburring, smoothing and polishing. 還有VTD PVD 超硬工具鑽石鍍膜 tool coating, 精密光學鍍膜 optical coating, 真空金屬鍍膜 metalization  absolute chemie PVD/CVD 退鍍工藝和 EMAG ECM / Precise Electrochemical Machining精密電化學加工技術, EMAG 硬車削/乾式切削 hard turning, Koepfer 滾齒加工製造技術, Reinecker, KARSTENS外圓研磨+內圓曲面磨削, Naxos-Union軸研磨凸輪軸, KOPP非圓研磨, SW中心加工機, EMAG 雷射焊接自動化設備. oelheld 超高性能研磨切削油/EDM 放電加工液等其它非相關資料純粹供同好分享