Effects of Vibration on the Preparation of Ultrathin Sections

1973 ◽  
Vol 31 ◽  
pp. 358-359
Author(s):  
Joseph M. Blum ◽  
Edward P. Gargiulo ◽  
J. R. Sawers
Keyword(s):  
Cutting Speed ◽  
Ground Level ◽  
Environmental Vibration ◽  
Block Face ◽  
Ultrathin Sections ◽  
Embedding Medium ◽  
Thickness Variations ◽  
Building Walls ◽  
Cutting Direction ◽  
Diamond Knife

It is now well-known that chatter (Figure 1) is caused by vibration between the microtome arm and the diamond knife. It is usually observed as a cyclical variation in “optical” density of an electron micrograph due to sample thickness variations perpendicular to the cutting direction. This vibration might be induced by using too large a block face, too large a clearance angle, excessive cutting speed, non-uniform embedding medium or microtome vibration. Another prominent cause is environmental vibration caused by inadequate building construction. Microtomes should be installed on firm, solid floors. The best floors are thick, ground-level concrete pads poured over a sand bed and isolated from the building walls. Even when these precautions are followed, we recommend an additional isolation pad placed on the top of a sturdy table.

scholarly journals How Long Should A Diamond Knife Stay Sharp?

1998 ◽  
Vol 6 (2) ◽  
pp. 6-7
Author(s):  
Charles A. Garber ◽  
Bernard Mesa
Keyword(s):  
Cutting Speed ◽  
Metal Particles ◽  
List Type ◽  
Distilled Water ◽  
Knife Edge ◽  
Razor Blade ◽  
Common Causes ◽  
Dry Down ◽  
Block Face ◽  
Diamond Knife

The answer to this question is about as elusive as predicting which way the Dow Jones average will close tomorrow! But seriously, there are the “ten commandments” for a diamond knife to enjoy a long life, the most important ones being as fallows:1)Because of the extreme sharpness of a diamond knife edge, it should not be touched with any solid object, even for cleaning, This is controversial since some manufacturers actually recommend that the edges be cleaned with sticks of varying types. We ourselves believe such treatment accelerates the wear of a diamond knife.2)Don't let sections or the remains of sections or other debris dry down onto the knife edge. Keep the knife edge wet until it is ready for cleaning before being put to bed for the night.3)Use a diamond knife cleaner sold by several firms (including ours) specifically for this purpose, Some typical laboratory ultrasonic cleaners can have enough power to be damaging to a knife.4)Wash the knife edge one last time with distilled water, and then dry with some kind of "blast", such as from a clean duster,5)Avoid conditions of chatter at all times. Reduce chatter by varying the clearance angle or slowing the cutting speed. Other common causes of chatter are insufficient tightening of the boat in the microtome, an insufficiently tightened block, or an incompletely cured block.6)Final block trimming with a razor blade can ieave metal particles from the blade, which are of course damaging to the knife edge, This can be minimized by using a fresh razor blade each time, Then wash the end of the freshly cut block face with distilled water, followed by drying with a duster blast is the final step before the first cut with the knife, This is a final chance to wash away metal particles that could damage the knife edge.

Surface Structure in Microtomed Sections Caused by Glass and Diamond Knives

1971 ◽  
Vol 29 ◽  
pp. 456-457
Author(s):  
J. Temple Black ◽  
William G. Boldosser
Keyword(s):  
Plastic Deformation ◽  
Epoxy Resin ◽  
Carbon Coating ◽  
Surface Damage ◽  
Body Angle ◽  
Normal Manner ◽  
Bottom Side ◽  
Cutting Direction ◽  
Made In ◽  
Diamond Knife

Ultramicrotomy produces plastic deformation in the surfaces of microtomed TEM specimens which can not generally be observed unless special preparations are made. In this study, a typical biological composite of tissue (infundibular thoracic attachment) infiltrated in the normal manner with an embedding epoxy resin (Epon 812 in a 60/40 mixture) was microtomed with glass and diamond knives, both with 45 degree body angle. Sectioning was done in Portor Blum Mt-2 and Mt-1 microtomes. Sections were collected on formvar coated grids so that both the top side and the bottom side of the sections could be examined. Sections were then placed in a vacuum evaporator and self-shadowed with carbon. Some were chromium shadowed at a 30 degree angle. The sections were then examined in a Phillips 300 TEM at 60kv.Carbon coating (C) or carbon coating with chrom shadowing (C-Ch) makes in effect, single stage replicas of the surfaces of the sections and thus allows the damage in the surfaces to be observable in the TEM. Figure 1 (see key to figures) shows the bottom side of a diamond knife section, carbon self-shadowed and chrom shadowed perpendicular to the cutting direction. Very fine knife marks and surface damage can be observed.

Effect of Cutting Parameters on Surface Roughness in Turning of Bone

2013 ◽  
Vol 845 ◽  
pp. 708-712 ◽  
Author(s):  
P.Y.M. Wibowo Ndaruhadi ◽  
S. Sharif ◽  
M.Y. Noordin ◽  
Denni Kurniawan
Keyword(s):  
Surface Roughness ◽  
Bone Tissue ◽  
Influencing Factor ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Cutting Conditions ◽  
Machining Process ◽  
Turning Operation ◽  
Cutting Direction

Surface roughness indicates the damage of the bone tissue due to bone machining process. Aiming at inducing the least damage, this study evaluates the effect of some cutting conditions to the surface roughness of machined bone. In the turning operation performed, the variables are cutting speed (26 and 45 m/min), feed (0.05 and 0.09 mm/rev), tool type (coated and uncoated), and cutting direction (longitudinal and transversal). It was found that feed did not significantly influence surface roughness. Among the influencing factor, the rank is tool type, cutting speed, and cutting direction.

Hole Surface Quality and Damage When Drilling Unidirectional CFRP Composites

2012 ◽  
Author(s):  
Eshetu D. Eneyew ◽  
M. Ramulu
Keyword(s):  
Significant Variation ◽  
Thrust Force ◽  
Cutting Speed ◽  
Polycrystalline Diamond ◽  
Surface Damage ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Cfrp Composite ◽  
Cutting Direction

In this study, an experimental investigation on the drilling of unidirectional carbon fiber reinforced plastic (UD-CFRP) composite was conducted using polycrystalline diamond (PCD) tipped eight facet drill. The quality of the drilled hole surface was examined through surface roughness measurements and surface damage by scanning electron microscopy (SEM). It was found that, fiber pullout occurred in two specific sectors relative to the angle between the cutting direction and the fiber orientation. The thrust force was highly influenced by the feed rate than the cutting speed and it shows a significant variation throughout the rotation of the drill.

Exploration of Local Blade Motions During Blade Shaping for Thick Layered Foam Cutting

2004 ◽  
Author(s):  
J. J. Broek ◽  
A. Kooijman
Keyword(s):  
Strain Energy ◽  
Cutting Tool ◽  
Cutting Speed ◽  
General Rule ◽  
Free Form ◽  
Linear Change ◽  
Minimum Strain Energy ◽  
Blade Cutting ◽  
Tool Position ◽  
Cutting Direction

The FF-TLOM (Free Form Thick Layered Object Manufacturing) technology is a Rapid Prototyping process based on flexible blade cutting of polystyrene foam. The heated blade is shaped by three parameters, which allows an infinite amount of minimum strain energy blade shapes with none, one or two inflexions. In the shaping domain stable and unstable blade shapes can exist. Stable shapes are defined as curves with none and one-inflexion and are applied for operational cutting of foam layers with the FF-TLOM technology. The tool motions are generated from the static tool poses and are calculated for a linear change of the flexible blade, when the cutting tool moves from one tool position to the next. The cutting blade is positioned to the foam slab with help of a point relative positioned on the flexible blade. The tool frame is positioned with a point fixed relatively to the tool frame. During the tool motions the blade curvature is changed and will introduce a shift of the half way point fixed on the blade (especially in the case of asymmetrical support inclinations and high curvature). Next the local displacement of the blade points in the bending plane of the blade due to blade shaping and tool pitching are quantified during the tool motions. These displacements induce an angle of attack of the blade in cutting direction, and will influence cutting speed and cutting accuracy. The quantification software is developed and will be used in the future for an overall prediction of the total tool curve displacements due to blade shaping, such as roll, pitch, yaw and linear positioning motions of the tool. A general rule for FF-TLOM cutting is minimization of all tool motions, which are not related to the forward cutting motion.

Machining Conditions Effect to Machining Temperature and Forces in Orthogonal Machining of Bone

2013 ◽  
Vol 658 ◽  
pp. 223-226 ◽  
Author(s):  
Denni Kurniawan ◽  
N. Jiawkok ◽  
M.Y. Noordin
Keyword(s):  
Analytical Study ◽  
Cutting Speed ◽  
Tool Geometry ◽  
Depth Of Cut ◽  
Machining Processes ◽  
Allowable Limit ◽  
Machining Conditions ◽  
Orthogonal Machining ◽  
Dental Implantation ◽  
Cutting Direction

Bone machining processes are often performed in orthopaedic surgery and dental implantation, yet its analytical study is lacking. Towards contributing analysis on bone machining, this study reviews available references on orthogonal machining of bones. Considering the allowable limit in temperature and duration during bone machining to avoid thermal necrosis, machining temperature and forces are the machining responses of interest. Machining conditions (cutting speed, depth of cut, cooling method, tool geometry, and cutting direction) are analyzed in term of their effect to those machining responses.

scholarly journals Improved Sectioning of Polymers Using an Oscillating Diamond Knife for Transmission Electron Microscopy

2006 ◽  
Vol 14 (5) ◽  
pp. 20-21 ◽  
Author(s):  
J.D. Harris ◽  
J.S. Vastenhout
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Wedge Angle ◽  
Cutting Speed ◽  
Sample Surface ◽  
Section Thickness ◽  
Thin Sections ◽  
Transmission Electron ◽  
Surface Section ◽  
Diamond Knife

Polymers are viscoelastic materials that can often deform during microtome sectioning. Similar to plastic embedded biological materials, many methods have been developed over the years to not only improve the image contrast of these materials but also to harden the material for improved sectioning during microtomy. Even with these improvements, a common artifact, compression, during the sectioning of this class of materials remains problematic.Compression is caused by several factors: hardness of the sample, embedding media, wedge angle of the knife, interaction between the diamond and sample surface, section thickness and cutting speed. It has been found that reducing the knife angle from 45º to 35° leads to a reduction in compression. Recent efforts to further reduce the compression of ultra-thin sections have led to the invention of an oscillating diamond knife.

scholarly journals An Effective Method of Preparing Sections of Bacillus polymyxa Sporangia and Spores for Electron Microscopy

1960 ◽  
Vol 7 (2) ◽  
pp. 373-376 ◽  
Author(s):  
Pauline E. Holbert
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Electron Micrographs ◽  
Epoxy Resins ◽  
Bacillus Polymyxa ◽  
Thin Sections ◽  
Similar Images ◽  
Embedding Medium ◽  
First Time ◽  
Diamond Knife

Bacillus polymyxa sporangia and spores were prepared for examination in the electron microscope by methods whose critical features were apparently: judicious use of vacuum, to encourage complete penetration of the embedding medium; the use of epoxy resins as embedding media; and cutting of the thin sections with a diamond knife. Electron micrographs of material prepared in this manner exhibit undeformed sporangial sections. Some of the structures revealed have been shown before, though perhaps less distinctly; other structures are revealed here for the first time. While this single study does not pretend to elucidate all the complexities of sporulation in bacteria, these and similar images should make this possible, and some mention of the preparatory techniques that lead to them seems advisable at this time.

The Technology in Sample Preparation for Transmission Electron Microscopy and Ultrastructure Observation of Lung Tissue in Rats with Experimental Silicosis

2014 ◽  
Vol 875-877 ◽  
pp. 695-698
Author(s):  
Qian Li ◽  
Li Juan Zhang ◽  
Fang Yang ◽  
Wen Li Zhang ◽  
Hong Xu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Sample Preparation ◽  
Success Rate ◽  
Cutting Speed ◽  
Ultrastructural Changes ◽  
Histological Changes ◽  
Transmission Electron ◽  
Ultrathin Sections ◽  
Perfusion Fixation

ts hard to get ideal ultrathin sections because of the adamant SiO2 dust in silicosis, after perfusion fixation methods and strict control of the cutting speed, improving the success rate of the Silicosis tissue TEM sample preparation of ultrathin sections,so we can more clearly and accurately observed ultrastructural changes of silicosis,and it also can offer morphological basis for research the silicosis organizations function histological changes.

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