Wear Mechanisms in Grinding of PCBN

2016 ◽  
Vol 1136 ◽  
pp. 555-560 ◽  
Author(s):  
Berend Denkena ◽  
Thilo Grove ◽  
Leif Behrens

PCBN-inserts have a high potential in the cutting of hardened steel, cast iron and super alloys due to their high hardness and heat resistance. Nevertheless they have a high purchase price, which lowers the economic benefits for the end user compared to other cutting materials. This is caused by the high production costs of the inserts. The grinding of PCBN-inserts causes a major proportion of these costs as a result of the high grinding wheel wear. The primary wear mechanism is grain breakout followed by clogging of the grinding layer. This study shows that the efficiency of the grinding process can be increased significantly by applying low cutting speeds and high feed rates. In this case, splintering of the grinding grain is the main wear mechanism.

2011 ◽  
Vol 325 ◽  
pp. 276-281 ◽  
Author(s):  
Manabu Iwai ◽  
Shinichi Ninomiya ◽  
Kiyoshi Suzuki

Polycrystalline Composite Diamond (PCD) is excellent in chipping resistance despite its very high hardness. However, it is not easy to EDM or grind PCD. To realize high efficiency and high quality processing of PCD simply and at low cost, the authors devised new PCD (EC-PCD) by using electrically conductive diamond particles and applied a complex electrodischarge grinding method. In this study, investigation is made on effective grinding condition to realize high efficiency, low and stable grinding force and low wheel wear in complex electrodischarge grinding. As a result, superior grinding property was obtained when the grinding wheel was set at minus polarity, and set peak current of iP = 4 and 6 A was applied. Furthermore it also became clear that additional conventional grinding process followed after complex electrodischarge grinding improved the surface condition.


2015 ◽  
Vol 658 ◽  
pp. 120-124
Author(s):  
Tachai Luangvaranunt ◽  
Natthawat Tangkaratanakul ◽  
Patchanok Sakultantimetha

Diamond grinding wheel is used in high precision grinding process, when work piece has a very high hardness. For a specific grinding interval, the wheel must be properly dressed, in order to remove swarf, sharpen the worn diamond grits, open up new diamond protrusions, and recondition the bond material. Dressing of diamond grinding wheel by alumina dressing tool has been simulated in a pin-on-disk machine in the research. Sharpening of the wheel is indicated by the increase of its roughness value, and surface microstructure with protruding sharp diamond grits. It was found that increasing of sliding distant from 100 to 500 m will increase the roughness of the wheel. The increase of contact load from 10 to 20 N will also increase roughness of the wheel, and the severity of wheel wear, indicated by high values of friction coefficient. A proper dressing of this nickel bonded SD1200 diamond wheel is by sliding against alumina dressing tool for at least 300 m under 10 N load. Sliding velocity has minimal effect to the results. A too large sliding distant and load will cause severe damage to wheel surface, and severe wheel wear, indicated by its large mass loss.


Author(s):  
M.A. Younis ◽  
H. Alawi

The high hardness and chemical effects of tool steels M2 and T15 cause a rapid grinding wheel wear and micro structural changes in the ground surface. The performance of sulphur-, wax-, and varnish-impregnated grinding wheels in grinding hardened tool steels M2 and T15 is investigated and compared with the performance of conventional alumina wheels. Impregnation with sulphur had in all cases beneficial effects by decreasing the grinding forces, increasing the maximum metal removal rate, improving surface integrity, and increasing considerably the grinding ratio. It also gave cost saving compared to the plain grinding wheel. The improvement was a result of the sulphur being more efficiently supplied into the chip formation process as compared to using grinding coolant only.


2011 ◽  
Vol 204-210 ◽  
pp. 1503-1508
Author(s):  
Yan Li ◽  
Hui Fan He ◽  
Yong Liu ◽  
Biao Dan Zhao

In order to make more uniform wheel wear, save production and reduce production costs, we improve the production process and optimize the processing way with the interpolation algorithm and the speed distributed computing by making the error analysis. And then the production process is gradually developed into green, environmental, lower consumption, higher income process.


2012 ◽  
Vol 472-475 ◽  
pp. 2264-2269
Author(s):  
Dong Po Yang ◽  
Jian Min Han

To solve the problems such as poor ventilation and high production costs in the production of cricoid plastics, we analysis the reasons and look for solutions with Moldflow software to guide the new design and manufacturing of the mould. The poor ventilated structure is changed into a ventilation structure. A poor ventilation structure is changed to a good ventilation structure. Injection weight ratio was reduced from 35% to 15% - 20%, the gating system was improved, the molding process was optimized, ensuring product quality and save the cost, produced good economic benefits.


Author(s):  
Peidong Han ◽  
Ioan D. Marinescu ◽  
Anil Srivastava

Single crystal sapphire is of significant interest due to its combination of excellent optical, electrical, and mechanical properties. However, fine grinding of sapphire is quite challenging because of its high hardness and low fracture toughness, making it sensitive to cracking. Wheel loading is a common problem in conventional grinding of hard and brittle materials. ELID grinding shows great promise in achieving a mirror surface finish at a relatively high efficiency. ELID grinding of sapphire was investigated using acoustic emission. The effects of processing parameters on surface finish and acoustic emission signals were evaluated. Correlations were found among the dressing current intensity, surface finish and acoustic emission signals. A smoother surface was obtained using a higher dressing current at the cost of a higher wheel wear rate. The wheel wear mechanism in ELID grinding of sapphire was dominated by bond fracture because the bond strength is reduced by electrolysis. Results indicate that the acoustic emission technique has the potential to be used for monitoring ELID grinding process, detecting the condition of the grinding wheel, and investigating the mechanisms of ELID grinding.


2020 ◽  
Vol 51 (4) ◽  
Author(s):  
Abdullah & Al-Taye

This study was aimed at assessing marketing efficiency in the main sites of meat production of calf fattening fields in the private sector due to the importance of meat, especially red meat, which has essential nutrient for human body growth and high commodity prices depending on the measurement indicators used to suit the nature of the research conducted in calves fattening production fields in Gogjali region- Nineveh  (2018). The basic source data of the study is obtained from sources on the ongoing ground- marketing questionnaire of three levels, the producer, the wholesaler, the retailer and two fields groups of caste random sample. The first group included (100) fields with imported calves class. The second included (51) fields with local calves class. Whereas, according to the production and marketing costs indicator, the average of marketing efficiency (ME1 ) of marketed meat in both groups of claves fattening fields amounted (92.47, 93.39%) respectively for a kilogram which is a sign of high production costs and, according to the marketing margins indicator, the average of marketing efficiency (ME2 ) of marketed meat in both groups of claves fattening fields amounted (86.89,79.13 %) for per kg which is a sign of high marketing margins. Thus the study concluded a high value of marketing efficiency using the first scale with the fattening period time for both groups while marketing efficiency by using the second scale was characterized by the gradual decline in the imported fattening fields and a gradual rise in the local fattening fields.  The study recommends supporting production inputs (fodder, treatment), unifying markets and limiting the    importation of red meat importation  in order to obtain a good production and currency policy by which the production costs could be reduced to the minimum .


Animals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 2027
Author(s):  
Doaa Ibrahim ◽  
Tamer Ahmed Ismail ◽  
Eman Khalifa ◽  
Shaimaa A. Abd El-Kader ◽  
Dalia Ibrahim Mohamed ◽  
...  

Necrotic enteritis (NE) caused by Clostridium perfringens (C. perfringens) results in impaired bird growth performance and increased production costs. Nanotechnology application in the poultry industry to control NE outbreaks is still not completely clarified. Therefore, the efficacy of dietary garlic nano-hydrogel (G-NHG) on broilers growth performance, intestinal integrity, economic returns and its potency to alleviate C. perfringens levels using NE challenge model were addressed. A total of 1200 male broiler chicks (Ross 308) were assigned into six groups; four supplemented with 100, 200, 300 or 400 mg of G-NHG/kg diet and co-challenged with C. perfringens at 21, 22 and 23 d of age and two control groups fed basal diet with or without C. perfringens challenge. Over the total growing period, the 400 mg/kg G-NHG group had the most improved body weight gain and feed conversion efficiency regardless of challenge. Parallel with these results, the mRNA expression of genes encoding digestive enzymes (alpha 2A amylase (AMY2A), pancreatic lipase (PNLIP) and cholecystokinin (CCK)) and intestinal barriers (junctional adhesion molecule-2 (JAM-2), occludin and mucin-2 (Muc-2)) were increased in groups fed G-NHG at higher levels to be nearly similar to those in the unchallenged group. At 14 d post challenge, real-time PCR results revealed that inclusion of G-NHG led to a dose-dependently decrease in the C. perfringens population, thereby decreasing the birds’ intestinal lesion score and mortality rates. Using 400 mg/kg of G-NHG remarkably ameliorated the adverse effects of NE caused by C. perfringens challenge, which contributed to better growth performance of challenged birds with rational economic benefits.


2021 ◽  
Vol 3 (1) ◽  
pp. 19-36
Author(s):  
Tamás Mizik ◽  
Gábor Gyarmati

As Earth’s fossil energy resources are limited, there is a growing need for renewable resources such as biodiesel. That is the reason why the social, economic and environmental impacts of biofuels became an important research topic in the last decade. Depleted stocks of crude oil and the significant level of environmental pollution encourage researchers and professionals to seek and find solutions. The study aims to analyze the economic and sustainability issues of biodiesel production by a systematic literature review. During this process, 53 relevant studies were analyzed out of 13,069 identified articles. Every study agrees that there are several concerns about the first-generation technology; however, further generations cannot be price-competitive at this moment due to the immature technology and high production costs. However, there are promising alternatives, such as wastewater-based microalgae with up to 70% oil content, fat, oils and grease (FOG), when production cost is below 799 USD/gallon, and municipal solid waste-volatile fatty acids technology, where the raw material is free. Proper management of the co-products (mainly glycerol) is essential, especially at the currently low petroleum prices (0.29 USD/L), which can only be handled by the biorefineries. Sustainability is sometimes translated as cost efficiency, but the complex interpretation is becoming more common. Common elements of sustainability are environmental and social, as well as economic, issues.


2011 ◽  
Vol 496 ◽  
pp. 7-12 ◽  
Author(s):  
Takazo Yamada ◽  
Michael N. Morgan ◽  
Hwa Soo Lee ◽  
Kohichi Miura

In order to obtain the effective depth of cut on the ground surface, a new grinding process model taking into account thermal expansions of the grinding wheel and the workpiece, elastic deformations of the grinding machine, the grinding wheel and the workpiece and the wheel wear was proposed. Using proposed model, the effective depth of cut was calculated using measured results of the applied depth of cut and the normal grinding force.


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