Deep-hole Process Research Articles

Research on deep hole processing of titanium alloy by MA-DAD

Research on deep hole processing of titanium alloy by MA-DAD

Exploring surface integrity: Experimental investigation into abrasive waterjet deep hole drilling on ss 316L for biomedical applications

Precision drilling of difficult-to-cut materials with exceptional surface integrity is a crucial factor in producing advanced manufactured components in industries like aviation, automotive, defense, electronic, and medical devices. More specifically, deep hole drilling enables precise customization of prostheses, improving patient comfort and functionality. Abrasive waterjet deep hole drilling has become a vital drilling technique in many industries due to its adaptability and effectiveness in drilling intricate shapes on hard-to-cut materials. The interplay between process parameters and surface finish underscores the need for systematic investigation to enhance drilling efficiency and quality. In this research, an attempt has been made to explore the influence of abrasive waterjet deep hole process parameters viz water pressure and standoff distance on the surface integrity of the drilled holes for biomedical applications. A surface roughness tester has been used to evaluate surface roughness at three distinctive places, namely the top, middle, and bottom of the drilled holes. The investigation showed that surface roughness at the top of the holes is less as compared to the middle and bottom of the holes. The average surface roughness along the depth of the drilled holes is greatly influenced by water pressure. Additionally, the morphology of the drilled holes has been studied using a scanning electron microscope (SEM). SEM images revealed that the top surface of the drilled holes is free from defects.

Experimental study of ECDM using a porous electrode containing internal micropores

ABSTRACT In electrochemical discharge machining (ECDM), continuous renewal of electrolyte between the tool electrode and the workpiece guarantees stable discharge machining. Proposed in this paper is Porous-electrode ECDM (p-ECDM) using a tool electrode made of porous material containing micrometer pores. The rough surface of the porous electrode promotes electrolyte regeneration between the electrodes to produce a stable and relatively thin gas film. At the same time, the internal connected micropores are used to provide controlled gas flow to the processing area, reduce the energy consumption of electrolytic bubbles, and improve the discharge energy to achieve efficient ECDM processing. Experimental results indicate that compared with a solid electrode, the porous electrode has faster electrolyte renewal, smaller bubble volume, more-stable voltage characteristics, 22.55% less overcut, a 4.7% smaller heat-affected zone, and better deep hole processing ability. Experimental results for p-ECDM assisted by controlled airflow demonstrate a 54.23% increase in the material removal rate.

Experimental Investigation of Tool Wear and Machining Quality of BTA Deep-Hole Drilling in Low-Carbon Alloy Steel SA-5083.

Nuclear power tube plates are made from the high-strength, low-carbon alloy steel SA-5083, which has high values of toughness and plasticity, though it is forged with poor consistency and entails serious work hardening. It requires a large number of deep holes with a high machining accuracy and high surface quality to be processed. However, the quality of the processed holes is often not up to the standard of the Boring and Trepanning Association (BTA) for the deep-hole drilling of tube plates; this has led to deep-hole processing becoming a bottleneck in the manufacture of steam generators for the main equipment of nuclear power islands. The variation laws of the diameter, roundness, perpendicularity, roughness, microhardness, and residual stress in relation to the feed, speed, and drilling depth are explored in the macro- and micro-dimensions; also explored is the wear morphology of BTA drills. The internal influence mechanisms between them are revealed in order to provide a scientific basis for the control of surface quality and machining accuracy as well as the optimization of process parameters. Our research results indicate that the guide block wear is mainly concentrated at the top 1-2 mm and that the drilling depth and feed have a great influence on the machining diameter. The hole wall roughness is between 0.3 and 0.6 μm, the maximum microhardness is about 2.15 times the hardness of the matrix material, and the residual stress is compressive stress. With increases in the feed and drilling depth, the hole diameter and the roughness increase. With an increase in the speed, the roughness decreases and the compressive stress of the BTA deep-hole drilling wall increases.

Research on Deep Hole Machining Based on Aircraft Landing Gear

A landing gear is the main large bearing structural part of an aircraft. The change of material and structure makes the processing of the aircraft landing gear more difficult. Aiming at the structural characteristics of the aircraft landing gear deep cavity, the deep hole processing technique of a 300M steel workpiece was studied. A separated NC deep hole drilling and boring machine was adopted to process the workpiece. Cavity hole special cutting tools were introduced. Fixture and sealing mode were improved. NC programs were optimized. Thus, the processing problems of deflection, vibration, chip breaking and chip removal were solved. The workpiece with width to diameter ratio greater than 10 and surface roughness of hole is 3.2 μm was successfully machined by machining experiment, and the high efficiency machining of deep hole of ultra-high strength steel was realized. Thus the theoretical foundation is laid for the machining of complex cavity deep holes for cutting high-strength alloy materials.

Deep Hole Processing of Extra-long Outer and Inner Circle Parts

Deep Hole Processing of Extra-long Outer and Inner Circle Parts

Research on The Deep Hole Processing of Aramid Fiber Reinforced Composites

Aramid fiber reinforced composite is a new material with high strength and low density, which is widely used in weapon, automobile, aerospace and other fields. The material is difficult to process, drilling is the main processing method of the material. In the drilling process, it is easy to appear fluff, ablation, stratification and so on. As a result, it is difficult to guarantee the quality of traditional processing and seriously affects its performance. In this paper, the drilling force and temperature in the drilling process are studied, and the influence of temperature and force on the processing quality is analyzed, so as to provide reference for the low-damage processing of aramid fiber reinforced composites.

高精度アルミニウムダイカスト金型の深穴ドリル加工における高度熟練技能者の有する技術の自動加工への適用

The deep hole processing of the high die steel is important technique for manufacturing the die for aluminum die casting for alternative vehicles. The automatic deep hole processing for small diameter is difficult. The control parameters are important for the automatic deep hole processing because the inadequate parameters cause the drill breakage and the productivity decrease. Currently, the expert technicians having excellent skills manually carry out the deep hole processing to the die steel. If the automatic control parameters for the machining center can be obtained based on the skills of expert technicians, the automatic deep hole processing is become possible and the productivity improves. In this study, the appropriate feed speed and the appropriate cut depth in each step were investigated as the suitable control parameters based on the expert technician’s skills. The automatic deep hole processing tests were carried out with a machining center via the suitable control parameters. The product sample with many small deep holes was processed with the machining center via the suitable control parameters and the previous control parameters. The machining time via the suitable control parameters were 30 % lower than that of previous control parameters and the productivity improvement was achieved.

次世代自動車用高精度アルミニウムダイカスト金型の深穴ドリル加工における熟練技術の定量的評価

次世代自動車用高精度アルミニウムダイカスト金型の深穴ドリル加工における熟練技術の定量的評価

Development and Design of Detachable Deep Hole Variable Diameter Boring Tool Device

In order to solve the problem of deep hole processing, the inner reaming of small ends and large middle is difficult to process. Developed and designed a detachable deep hole variable diameter boring tool device with self-centering, replaceable tools, and capable of changing the same diameter of the guide block and the tool and with self-locking function. Introduce in detail the structural features, assembly conditions and design principles of the detachable deep hole variable diameter boring cutter device. It provides an effective solution for the processing of inner reaming in deep holes.

Study of Double-Edged Gun Drills with Different Edge Types in Drilling Compacted Graphite Iron

Deep-hole machining is an important part in the field of mechanical processing of diesel engine. Gun drill has been widely used in deep-hole machining because of its high dimensional accuracy, high efficiency and good straightness. Through experiments on drilling compacted graphite iron with two different edge types of double-edged gun drills, the spindle power, axial force and tool wear were analyzed and found out one edge type which is more suitable for processing compacted graphite iron. This paper presents a simulation of deep hole drilling to validate the analysis. The research results have important guiding significance for deep hole processing of compacted graphite iron.

Mechanical properties of helical milling deep hole on QFRP using cryogenic cooling process

The structure and physical properties of quartz fiber reinforced polyimide composite (QFRP) lead to the milling hole defects of crimp, ablation and delamination, as well as serious tool wear and limited hole making depth. Based on three kinds of defects of helical milling holes of composite materials, the cutting force model was constructed considering the cutting micro-zone temperature. This article presents the first comprehensive investigation on cryogenic (83K) milling deep hole process of QFRP through liquid nitrogen injection by carbide film blades with 10 mm cutting diameter. In this project, the surface morphology, cutting force, cutting temperature and tool wear performance were analyzed compared with dry milling ones. The results show that the three kinds of defects are all affected by cutting force and mechanical properties of composites. In dry milling shallow hole with low speed, the type I crimp defect of hole entry, the type II lamination defect of hole middle and exit are all serious, as well as the type III ablative defect of hole exit with 1.06 mm machining error at high speed. The milling hole cutting forces are mainly related to axial feed, tangential feed and composite properties considering temperature. At the same time, the axial and tangential forces are more affected by the change of tool axial feed than tangential feed. After cryogenic cooling intervention, milling hole defects and tool wear are well inhibited. And the accuracy of shallow hole was up to 0.03 mm at hole exit, as well as 0.05 mm for deep hole without delamination tear and ablation defects. Conclusion, the properties change of matrix and composite at low temperature are the main reason for preventing type I and II milling hole defects, and the eliminated passivation and adhesion of tool side blade and flank surface are the reasons for restraining type III defects.

Numerical simulation of multi-pulsed femtosecond laser ablation: effect of a moving laser focus

In femtosecond laser helical drilling, the laser focus moves downward into the workpiece as material is removed, which is one of the main features used to improve the processing efficiency. Numerical modeling is the primary method used to study this process. To reduce the spatial scale of the numerical model, the influence of the helical trajectory was not considered in this study. Instead, the influences of the pulse interval and the downward velocity of the laser focus on the ablation process during deep-hole processing with multi-pulse femtosecond laser ablation were explored, and the existing two-temperature model was adapted. We used the critical-point phase separation model to describe the material ablation process with a femtosecond laser. Using a copper workpiece, we simulated an ablation process in which multiple pulses from a femtosecond laser were focused onto the workpiece and the focus moved into the workpiece at a constant speed. We used the finite element method to determine the variation in the electron and lattice temperatures, as well as the ablation depth under different pulse intervals with the focus moving downward at different velocities. The results demonstrate that the pulse interval is an important factor affecting the ablation depth during multi-pulse femtosecond laser ablation. As the pulse interval increased, the ablation depth first increased and then decreased. The laser ablation efficiency was highest when the pulse interval was 200 ps. The downward velocity of the laser focus determined the defocusing distance during laser processing. We obtained a high processing efficiency when a reasonable downward velocity was adopted to maintain the defocusing distance within approximately 50 nm.

Research on Super-long Deep Hole Drilling Technology Based on 0Cr17Ni4Cu4Nb Stainless Steel

0Cr17Ni4Cu4Nb stainless steel has problems such as severe work hardening, serious tool wear and difficulty in heat dissipation in the deep hole processing. Thus the super-long deep hole drilling of 0Cr17Ni4Cu4Nb stainless steel was studied. The material and geometric parameters of drilling bit were selected reasonably. The super-long deep hole drilling test of 0Cr17Ni4Cu4Nb material was designed and carried out. The drilling process and reason for the axis deviation were investigated. The experimental results show that reasonable parameters of drilling bit and drilling process can better control the hole axis deviation. It provides technical parameters and experience for actual production.

Analysis of improving ways for dual nozzle negative pressure chip removal device in deep hole processing

In order to solve the problem of chip removal of the large-length-diameter ratios deep-hole machining, the negative pressure jet model is established on the basis of analysing the mechanism of DF system’s negative pressure chip removal. To solve the energy loss caused by the eddy current phenomenon in the front separation zone, this paper adopts two-stage injection method. The pre-nozzle is added in the front separation zone so that part of the jet fluid enters the front separation zone through this nozzle, reducing unnecessary energy in the front separation zone and increasing the negative pressure value. Through theoretical analysis and fluent simulation optimization experiments, the paper proved that jet angle of the new jet nozzle is 33 degree and the clearance is 0.4mm has the best effect. The negative pressure zone is the largest, and the pressure value in the negative pressure zone is reduced by about 50.7%, which minimizes the energy loss in the front separation zone and enhances the negative pressure chip removal capability

Improving the performance of EDM deep hole using multi-hole interior flushing electrode

In conventional flushing, when increasing the machining depth, the flushing ability becomes insufficient for ejection of the debris from machining gap. Debris concentration in the gap spark causes a process instability, low performance and high machining time etc. This paper proposes an innovative method of flushing technique for electrical discharge machining (EDM) of deep hole process. Tool electrode was specifically fabricated for flushing on the efficiency and stability of machining to promote the ejection of debris from machining gap. The performance of the deep hole process by electrical discharge machining under different flushing condition are presented. The results showed that the flushing through the tool electrode and multi-hole interior flushing are more preferred than side flushing. The result include 26.10% reduction in machining time (50 mm. in depth) when using multi-hole interior flushing electrode. In addition, the application of electrode multi-hole interior flushing electrode with electrode rotation improves the material removal rate (MRR) by 35.28% with 58.04% higher surface roughness (Ra).

ANSYS is Used on Drilling Inner Blind Hole on Deep Hole

In this paper, the process of drilling inner blind hole on deep hole is simulated in the finite element software ANSYS, which can directly reflect the different influence of the cutting force on the bit when drilling. According to the result, designed a deep hole inner blind hole processing auto-device, introduce the design concept and working principle of the device, establish the design model and the mechanical model of the drill bit. Carry out several technical experiments, proved the processing feasibility of the intelligent device; analyzed the problems occurred in processing and the factors that affect machining precision. With experiment results, put forward several deficiencies and improvements for intelligent device, provide important data for future improvement.

Tracing Algorithm of Workpiece Heat Flux in Deep Hole Processing

Tracing Algorithm of Workpiece Heat Flux in Deep Hole Processing

An investigation on dimensional accuracy of EDM deep hole using multi-hole interior flushing electrode

Improper flushing of dielectric fluid adversely affects the dimensional accuracy produced in EDM deep hole process. This paper investigates the dimensional accuracy (e.g. roundness error and gap clearance) in EDM deep hole process of AISI P20 tool steel. The inner flushing electrode is newly proposed in this study, using the multi-hole interior flushing technique coupled with electrode rotation. The results showed that the multi-hole interior flushing with electrode rotation improves the deviation of roundness error due to improved flushing. In addition, using multi-hole interior flushing with electrode rotation provides the cylindrical shape in gap clearance. Finally, a more powerful flushing technique is achieved with newly purposed multi-hole interior flushing technique on roundness error and gap clearance, respectively.

33-4: COA Technology Applied in ADS Mode LCDs

COA technology used in ADS mode LCDs is analyzed through theoretical method and basic experimental verification. Compared to IPS and VA mode LCDs, more films on R/G/B will cause the special process manufacturing issues for ADS mode LCDs. It mainly presents in three problems, which are process compatibility, flatness and deep-hole process. In this paper, the risk points of COA technology are put forward, and the possible solution is also analyzed.