Application of sandpaper depending on its grain size
On the Russian market, sandpaper is represented by two types of brands. The first are manufacturers of hand and power tools that sell various types of sandpaper under their own brands as consumables for their own products. The second group includes enterprises specializing in the production of tools, including abrasive ones. For example, Fit sandpaper is offered by a well-known Canadian brand that specializes in the sale of all types of hand and power tools. Among the Russian manufacturers, the most famous is the Belgorod Abrasives Plant, and among the foreign ones – the Finnish company Mirka and the famous international corporation 3M. The lion’s share of sandpaper on the Russian market is imported. It is mainly supplied from China under various trademarks, although a well-known brand such as Mirka produces its sandpaper in Taiwan. Against this background, 3M looks the best, having built its own plant in Volokolamsk in 2008..
Somewhat earlier, the Belgorod Abrasives Plant put into effect TU 3980-009-00223332-2003, which regulated the new marking of sandpaper using the international designation of grain size and other parameters (see the right diagram above). Prior to that, the marking code was applied in accordance with several GOSTs of 1982 (each for a certain type of base).
There are several types of abrasive paper grain designations, among which the most common are the systems of the Federation of European Abrasives Manufacturers (FEPA) and the American Institute of Abrasive Coating Manufacturers (CAMI). On the basis of the first, the international standard ISO 6344 was adopted in 1998, the second is widespread mainly in the USA. The FEPA marking is based on a numerical range of grit sizes in 21 grades ranging from 3 μm to 1 mm (see table on the left above). According to the quality type, abrasive powders for sandpaper are divided into two types: coarse-grained (from P22 to P220) and fine-grained (from P240 to P2500). The size of the smallest grinding grain according to this classification is 3–5 microns, which corresponds to the old GOST number of sanding paper for polishing H0 (popular name – “zero”).
Types of sandpaper, its marking and production
Sandpaper: forms of release, types of abrasives, markings and major manufacturers of sandpaper. Grain classes. Features paper-based and fabric waterproof skins. Manufacturing technology. Holder types.
When grinding, pre-polishing and finishing the cutting edges, grinding wheels, flat bars or flexible sheet materials coated with abrasive grit are usually used as tools. The latter have two widespread names: folk – sandpaper (sandpaper), and the official GOST – sandpaper. The common name has been preserved since the times when natural corundite powder (emery) was used as an abrasive, and thick paper was used as a base. Now, instead of natural minerals, abrasives obtained by an industrial method are used. Among them, the most common are granular powders based on aluminum oxide, silicon carbide and boron nitride. The basis for modern sandpaper can be not only paper, but also fabric, polyester, fiber or combined, and waterproof and electrostatic adhesives are now used as a bond. Initially, sandpaper was only used for hand sanding. But in the second half of the twentieth century, in connection with the creation of high-strength bases, it began to be widely used in machine grinding: first on belt and drum machines, and then on vibratory and orbital grinders..
Selection tips for specific types of work
- plain and latex paper;
- cotton and blended (x / synthetics) fabrics;
- polyester fabrics;
- combined materials (usually paper-cloth).
The paper is classified by weight in six ranges from 85 g / m² to 500 g / m², and the main technological feature of fabrics, in addition to their composition, is flexibility. This parameter has six gradations: from “extra flexible” and “very flexible” to “hard” and “extra hard”. In addition, all sandpaper, regardless of the basis, is divided into regular and waterproof..
The main advantages of paper-based sandpaper are low price and resistance to stretching. And its main drawback is low mechanical resistance and brittleness at the folds. Cloth-based abrasive paper has high tensile strength and can be used in belts for machine sanding. In addition, it is flexible and easily takes the shape of the sanding surface. And waterproof fabric bases do not lose their working qualities when wet sanding or working in high humidity conditions. To obtain combinations of mechanical properties of various materials (flexibility and inability to stretch), sandpaper with a two-layer base impregnated with polyester resins is produced..
Sandpaper release form
Abrasive paper is used not only for manual but also for machine grinding, so it is available in a wide variety of forms.
In addition, sandpaper is an integral part of the flap brushes. In this case, it is used in the form of a set of narrow sandpaper lamellas, fixed at one end around the entire circumference of the central sleeve (see in the photo above – on the left in the background).
- Electrocorundum. Artificial material containing up to 99% aluminum oxide. Quite inexpensive and therefore the most common among abrasives. In addition to normal and white, a number of varieties are produced with additives of titanium, chromium, zirconium compounds, etc..
- Silicon carbide. Compared to electrocorundum, it is more fragile, but surpasses it in hardness, therefore it is used mainly for metal work. Available in two types: green and black, which differ slightly in cutting properties.
- Garnet. A natural mineral, inferior in hardness to all others, but self-sharpening well. Main application – grinding soft materials.
- Elbor. Synthetic boron nitride abrasive. Hardness is somewhat inferior to diamond, but has better heat resistance.
- Diamond. Has the highest hardness. Diamond sandpaper is used for processing hard alloys and finishing tools.
In addition, abrasive paper based on natural corundite (emery) and glass powder is still produced. The latter, in accordance with the standards, is used for grinding collectors of electric motors and generators..
FINISHING TYPES. TECHNOLOGY OF GRINDING AND POLISHING OF PRODUCTS
Section 2 Manufacturing technology of products from sheet metal and wire
Topic 2.5. Finishing of sheet metal and wire products by grinding and polishing
§ 13. TYPES OF FINISHES. TECHNOLOGY OF GRINDING AND POLISHING OF PRODUCTS
Remember what technological operation is called product finishing.
What preparatory operations are performed when finishing wood products?
What is the sanding paper for??
To give metal products a beautiful appearance and protect them from corrosion (rusting), which
Grinding is the process of cutting structural materials using an abrasive tool, the cutting element of which is grains. The grains, which have high hardness and sharp edges, are combined with special connecting substances into sanding skins. Depending on the purpose, they have a certain shape. For manual grinding, they are made in the form of separate sheets, for machine grinding – in the form of long belts or circles, etc. (Fig. 148). The grade of the skin is indicated
The protruding grains of abrasive material are securely attached to the abrasive paper. As it moves along the surface to be treated, they cut (scratch) the metal layer in the form of very small chips. A large number of chips are involved in cutting (scratching), their small thickness (several microns) is due to the small size of the cutting grains themselves and their large number. Grinding ensures high precision and slight roughness (unevenness) of the processed surface. Therefore, this process is most often the final technological operation in the finishing of products..
The specified technological operation, as in the grinding of wood materials, is performed manually and with special grinding machines.
For manual grinding, use a thin section with a sandpaper attached to it or ready-made grinding stones (Fig. 149).
For grinding metal surfaces, sandpaper with a grain size from 200 to 12 is used. The lower the number of grain size, the finer the abrasive grain, and, consequently, the higher the processing accuracy (Fig. 150).
Most of the abrasive papers are of foreign origin. Accordingly, we see a different marking on the sanding paper. When marking abrasives according to the scale of the Federation of European Abrasive Manufacturers, the letter index “P” is placed before the number. Abrasive grain size is referred to as the grit number based on the number of meshes per linear inch of mesh through which the abrasive is sieved during screening. So, the sanding paper with the inscription P40 has large grains, and the sanding paper with the inscription P400 has fine grains and is used for fine grinding..
Before you start sanding the metal surface, it is cleaned of rust with a metal brush..
Rust is a red-brown film that forms on the surface of steel as a result of its interaction with moisture, air and other factors (Fig. 151). As a result of such interaction, parts of cars, trains, machine tools, instruments, machines and mechanisms from which they are constructed rust..
Untimely removal of rust from the metal surface can lead to unpredictable consequences. For example, due to an oversight of the state of metal structures, this phenomenon caused the destruction of the bridge over the Mianus River (Connecticut, USA) in 1983, when the support of the lifting mechanism was completely rusted from the inside. As a result, this mechanism caught on the corner of one of the road plates and moved it off the supports. Rust was also a major factor in the destruction of the Silver Bridge over the Ohio River in West Virginia in 1967, when the steel suspension bridge fell in less than a minute (Fig. 152, a)..
Keenzu Bridge in Pennsylvania (Figure 152b) was torn down by a tornado in 2003, in large part because the central base bolts connecting the structure to the ground were corroded and the bridge was held simply by gravity..
You can protect products from rust with paint and varnish and other protective coatings that insulate iron from environmental influences. Large areas divided into sections, such as the hulls of ships and modern cars, are often coated with paints, wax-based products (technical canning oil).
Before this technological operation, it is necessary to remove the rust..
Manual metal cleaning is a method of preparing metal surfaces using hand tools. The specified technological operation is performed using sanding skins, hand wire brushes, spatulas, scrapers, etc. (Fig. 153).
The most widespread is the performance of cleaning with the help of electrified tools with special circles fixed on them (Fig. 154).
After this technological operation, grinding is performed.
For sanding by hand, the sanding cloth is fixed on wooden whetstones – thin sections. Grinding of surfaces is performed by reciprocating or circular motions of a thin section or abrasive paper on the surface to be treated (Fig. 155).
Better surface, with good gloss and high corrosion resistance, obtained by polishing.
Polishing – elimination of minor irregularities from the surface. It is performed after thorough grinding with special pastes – varnishes..
Mechanical polishing is performed with polishing wheels or plates made of felt or cotton fabrics with paste applied to them, micropowders of the M-5, M-7, M-10, M-14, M-20, M-28 brands (the numbers indicate the grain size in micrometers ) or polishing pads No. 280 and No. 325 (fig. 156).
Currently, these works are performed using universal grinding and polishing machines with special attachments fixed on them (Fig. 157).
When polishing by hand, the paste is applied to the felt and made circular movements along the surface of the product, or appropriate polishing pads are used for this. When polishing with pastes, a felt swab is fixed in the hand so that it is firmly held in the palm of the hand (Fig. 158).
After that, paste is applied to the tampon and moved over the surface (Fig. 159).
Sanding is done in the same way as sanding.
When grinding and polishing metal products, the following safety rules must be observed:
There should be nothing superfluous in the workplace.
Work should be done with gloves and glasses.
Grinding and polishing of flat workpieces should be done on a backing board.
Do not touch the abrasive paper and sharp parts of the workpiece with your hands..
It is forbidden to blow off the waste, you can sweep them only with a brush – a sweep.
You need to protect your face and eyes from dust and waste that is formed during rust removal, sanding and polishing.
PRACTICAL WORK 4
Grinding and polishing products
Equipment, tools and materials: products made in previous lessons, sanding skins of various brands (coarse, medium, fine), metal brush, felt swab, sanding, vice, polishing paste.
As instructed by the teacher, inspect the previously made product.
Determine what types of work need to be done to finish it.
Perform rust removal, sanding and polishing of the product.
Check the quality of the work done.
– grinding, polishing, sanding, sanding paper, abrasive material.
Abrasive material is a very hard material used for grinding, polishing, turning.
Finishing – giving the product a beautiful appearance.
Paste – viscous pasty substance.
Felt – a dense, thick material made of felted wool or synthetic fibers.
Felt is a dense felted material made from high quality wool.
Grinder – a device designed for attaching a sanding cloth.
What phenomenon is called metal corrosion? How to prevent it?
What technological operation is called grinding? polishing?
What is the purpose of grinding and polishing products??
What materials are grinding skins made of??
What is the name of the process of giving a product a beautiful appearance by grinding and polishing?
A decoration B equipment
B finish D painting
What is the general principle underlying the operation of the tools shown in the figure?
All of the above
There is no right answer
In which device is the grinding skin fixed for processing metal workpieces?
In the clamps of the carpentry machine
All answers are correct
There is no correct answer
What technological operation precedes the grinding of the workpiece for the manufacture of the product?
D cleaning from rust
E all of the above
The Only 3 Sandpapers You Really Need | SANDING BASICS
There is no right answer
What technological operation precedes the polishing of the workpiece in the manufacture of the product?
D cleaning from rust
All of the above
3 there is no correct answer
What parameters determine the roughness of the sanding paper?
And the hardness of the base material on which the abrasive is applied
Used abrasive material that is applied to the substrate
The particle size of the abrasive that is applied to the substrate
All of the above
There is no correct answer
TYPES OF CONNECTIONS OF THIN SHEET METAL PARTS. TECHNOLOGY OF BENDING THIN-SHEET METAL. CONNECTION OF PARTS WITH SINGLE FOLDED SEAM Section 2 Technology of manufacturing products from thin sheet metal and wire Topic 2.3. Methods of joining parts of thin sheet metal § 10. TYPES OF CONNECTIONS OF PARTS FROM THIN SHEET METAL. TECHNOLOGY OF BENDING THIN-SHEET METAL. CONNECTING PARTS WITH SINGLE FILLER SEAM 1. Remember what types of joints of parts made of structural materials you know. What is their essence? What do they have in common and in […].
FINISHING PRODUCTS BY PAINTING Section 2 Manufacturing technology of products from sheet metal and wire Topic 2.5. Finishing of products made of sheet metal and wires by grinding and polishing § 14. FINISHING PRODUCTS BY COLORING 1. What is the essence of technological operations carried out when finishing products? 2. What methods of finishing are known to you? 3.What is the purpose of finishing products? 4. What is the finishing technology […].
PRODUCTION OF PRODUCTS FROM WIRE Section 2 Technology of manufacturing products from thin sheet metal and wire Topic 2.4. Technology of alignment, marking, cutting of wire § 12. MANUFACTURE OF PRODUCTS FROM WIRE 1. What stages does the design of products from thin sheet metal consist of? 2. What is common and what is the difference between the design of wood products and sheet metal? 3. What product is called an analogue? model? layout? […].
TECHNOLOGY OF OVERVIEW OF BILLS ON SHEET METAL Section 2 Technology of manufacturing products from sheet metal and wire Topic 2.1. The process of marking blanks on sheet metal § 7. TECHNOLOGY of marking blanks on sheet metal 1. Remember what technological process is called marking. 2. What line is called the base line? 3. What is an allowance? What is it for? 4. What device is called a template? What is its purpose? five. […].
TECHNOLOGY OF SILING BILLS FROM THIN-SHEET METAL Section 2 Technology of manufacturing products from thin-sheet metal and wire Topic 2.2. Technology of cutting and filing of parts from thin sheet metal § 9. TECHNOLOGY OF Sawing off workpieces from thin sheet metal 1. What tools are designed to control dimensions? 2. Which part of the tool is called a cutter? 3. What types of files do you know? What do they have in common and what is the difference? […].
TYPES OF CONNECTIONS OF PARTS Section 3. Fundamentals of engineering, technology and design Topic 3.1. Mechanisms and machines. Drilling machine § 17. TYPES OF CONNECTION OF PARTS 1. Why are parts connected? 2. What methods of joining parts do you know? 3. What connection is called riveted? The parts that make up the machines are connected in different ways. Some details are connected “forever”, others – so that they can be […].
STRAIGHTENING OF THIN-SHEET METAL. TOOLS AND MATERIALS FOR STRAIGHTENING Section 2 Manufacturing technology of products from sheet metal and wire Topic 2.1. The process of marking blanks on sheet metal § 6. STRAIGHTENING OF THIN SHEET METAL. TOOLS AND MATERIALS FOR STRAIGHTENING 1. What technological operations precede the marking of products? 2. What preparatory work steps do you think should be performed to mark sheet metal blanks? Straightening is a technological […].
SURFACES OF GEOMETRIC BODIES Section 2 Manufacturing technology of products from sheet metal and wire Topic 2.1. The process of marking blanks on sheet metal § 5. DEVELOPMENTS OF SURFACES OF GEOMETRIC BODIES 1. Remember which geometric bodies are called volumetric. 2. What kind of mowing line is used for dimensioning the drawing? 3. How to dimension the drawing correctly? 4. Remember what geometric body is called a cube, a circle, […].
COMBINATION METHOD Section 3. Fundamentals of engineering, technology and design Topic 3.2. Basics of design activity § 22. METHOD OF COMBINATION 1. What is the essence of using bioforms in the design of objects? 2. How is the method of fantasizing used to design products? Designing new products is a creative process. The result of this activity is a product with a better set of properties and compliance with the requirements for a particular case. […].
CONNECTION OF PARTS WITH RIVES Section 2 Manufacturing technology of products from sheet metal and wire Topic 2.3. Methods of joining parts made of thin sheet metal §11. CONNECTING PARTS WITH RIVETS 1. Why are parts connected? 2. What methods of joining parts do you know? 3. What safety rules must be followed when joining sheet metal parts? Widespread in the construction of aircraft, ships, television towers, […].
THE CONCEPT ABOUT THE PRODUCTION OF THIN-SHEET METAL, ITS TYPES AND PROPERTIES Section 1. Fundamentals of materials science Topic 1.1. Types and purpose of construction materials. Thin sheet metal and wire § 2. CONCEPT ABOUT THE PRODUCTION OF THIN SHEET METAL, ITS KINDS AND PROPERTIES 1. Remember what construction materials you already know. 2. Explain why different materials of construction are used for the manufacture of products. 3. Remember the properties of wood construction materials known to you. What are their […].
METHODS OF CUTTING THIN SHEET METAL Section 2 Technology of manufacturing products from thin sheet metal and wire Topic 2.2. Technology of cutting and filing of parts made of thin sheet metal § 8. METHODS OF CUTTING THIN SHEET METAL 1. What technological process is called cutting? 2. Think about the general principle behind cutting with scissors and saws. 3. What is called the cutting edge of the tool? 4. How is […].
GRAPHIC IMAGES. MAIN MOWING LINE DRAWINGS. SCALE Section 2 Manufacturing technology of products from sheet metal and wire Topic 2.1. The process of marking blanks on sheet metal § 4. GRAPHIC IMAGES. MAIN MOWING LINE DRAWINGS. SCALE 1. Is it possible to make a product according to a drawing? 2. From which document can you find out about the shape and dimensions of the product? 3. What safety rules and sanitary and hygienic requirements should be observed when performing […].
Circumstance and its types by meaning LESSON № 21 Topic. Circumstance and its types by meaning Purpose: to deepen students’ knowledge of the circumstance; familiarize them with the types of circumstances by value; develop logical thinking in children; foster interest in the Russian language. Expected Outcomes: Students highlight a circumstance on the issue; distinguish types of circumstances by meaning; use circumstances in speech. Equipment: textbook, didactic material. Lesson type: […].
CONCEPT OF WIRE MANUFACTURING, ITS KINDS AND PROPERTIES Section 1. Fundamentals of materials science Topic 1.1. Types and purpose of construction materials. Thin sheet metal and wire § 3. CONCEPT OF WIRE MANUFACTURING, ITS TYPES AND PROPERTIES 1. Remember the technology of production of thin sheet materials on rolling mills. 2. What is the state of the metal during rolling? 3. What properties of structural materials do you know? What is their essence? 4. For […].
TYPES AND EFFECTS OF CONFLICTS SECTION 4 SOCIAL COMPONENT OF HEALTH Chapter 1. Social well-being § 23. TYPES AND EFFECTS OF CONFLICTS In this paragraph you: find out why between people there are conflicts; learn to distinguish between conflicts of views and conflicts of interest; learn about ways to resolve conflicts; practice recognizing conflicts in everyday life. Conflicts are part of a relationship 1. Pair up […].
CONCEPT ABOUT DESIGN FEATURES OF TECHNOLOGICAL ACTIVITIES Section 3. Fundamentals of engineering, technology and design Topic 3.2. Fundamentals of design activities § 21. CONCEPT OF THE FEATURES OF DESIGNING OBJECTS OF TECHNOLOGICAL ACTIVITY 1. Think about whether all the objects that are created in the production process can be attributed to objects of technological activity. 2. In your opinion, can trees growing in parks and squares be objects of technological activity? 3. What […].
The main types of subordinate parts. Subordinate unions, allied and indicative words DIFFICULT SUBJECT PROPOSALS LESSON № 15 Topic. The main types of subordinate parts. Subordinate unions, alliance and indicative words Purpose: to deepen the knowledge of students about a complex sentence; to consolidate the concepts of subordinate union, union words; learn to find index words, determine the type of the subordinate part; develop skills in parsing and drafting sentences; foster a culture of speech, love of reading and fiction. Equipment: […].
INFORMATION SOURCES. SEARCH FOR INFORMATION Section 3. Fundamentals of engineering, technology and design Topic 3.2. Fundamentals of design activities § 20. INFORMATION SOURCES. SEARCH FOR INFORMATION 1. For what purpose is the combination method used? 2. Why is a reference product used in combination? 3. Where can you find similar sample products? To design any product, it is necessary not to immediately make drawings on a sheet of paper, but to get acquainted with the product and find […].
Types of sentences Russian language – Russian language Syntax and punctuation Sentence A sentence is the smallest unit of communication, which is a grammatical and intonationally complete expression of an individual thought. Types of sentences According to the purpose of the statement: – narrative (express the message): The earth is great and beautiful. (Ch.) – interrogative (expressing a question): Do you know the Ukrainian night? (G.) – incentive (express an urge to […].
INTRODUCTION Dear friends! We are glad to welcome you to the land of Masters again. You already know many of her secrets and secrets. And so you can guess why this country is also called the country of dreams. Have you guessed? Correctly! Because in our country the dreams of those who know how to work with soul, respect labor and people of labor come true. We will learn all this […].
Sentence. Types of sentences Lesson 43 Sentence. Types of offers We learn new information about the offer, different types of offers 302. Guess riddles. 1. Well done, your name is, If you really love…. 2. Relaxing carefree, If done…. What do you think, are the answers to these riddles close in meaning? 303. Compare a group of words. Which one is the offer? Why? 1. The student diligently […].
Types of connection of words in word combinations Russian language – Russian language Syntax and punctuation Word combination Types of connection of words in word combinations 1. Coordination. The dependent word has the same gender, number and case as the main thing: 2. Management. The dependent word is in the same case as the main word requires: 3. Adjacency. The dependent word is related to the main one only in meaning (the dependent word is […].
Types of syntactic connections between parts of a complex sentence. Complicated sentences with composition and submission COMPLEX Sentences WITH DIFFERENT TYPES OF COMMUNICATION LESSON № 48 Topic. Types of syntactic connections between parts of a complex sentence. Complex sentences with composition and submission Purpose: to deepen students’ knowledge of a complex sentence; to acquaint with various types of syntactic relations between parts of these structures; teach to correctly place punctuation marks; develop skills in parsing and drafting sentences; develop creative […].
One-piece sentences. Types of one-part sentences SIMPLE PROPOSAL LESSON № 24 Topic. One-piece sentences. Types of one-part sentences Purpose: to deepen the knowledge of students about the types of proposals for the structure, to acquaint with the types of one-part sentences; to form the ability to correctly identify such sentences, to distinguish them from two-part ones; develop oral and written speech, improve skills and abilities to work with text, as well as with learned spelling; educate an aesthetic taste. […].
HEALTHY TEETH Section 1 HEALTHY BODY HEALTHY TEETH Which of these animals are called rodents? Which of these animals have no teeth? Which of these animals bite without teeth? Use a mirror to count how many teeth you have. What are teeth for? There are many animals in nature that cannot survive without teeth, because with their help they extract […].
Sentence. Types of sentences for the purpose of the statement. Capital letter at the beginning of a sentence. The use of nouns in the dative plural with a preposition (on the road, through the pages) I SEMESTER LESSON 10 Topic. Sentence. Types of sentences for the purpose of the statement. Capital letter at the beginning of a sentence. The use of nouns in the dative case of the plural with a preposition (along the roads, through the pages) Purpose: to systematize students’ knowledge about the sentence; teach to correctly highlight the boundaries of the sentence in oral and written speech; develop coherent speech of students; to educate accuracy, attentiveness. Lesson type: combined […].
Types of complex sentences: allied and non-allied. Punctuation marks. Intonation in complex sentences DIFFICULT Sentence. COMPLICATED PROPOSALS LESSON № 9 Topic. Types of complex sentences: allied and non-allied. Punctuation marks. Intonation in complex sentences Purpose: to deepen students’ knowledge of a complex sentence; teach to distinguish between the types of complex sentences (allied, non-allied), correctly place punctuation marks; be able to use the intonation richness of the Russian language; foster a culture of speech, love of reading and fiction. Equipment: textbook, […].
The structure and types of word combinations by the type of subordinate connection WORD COMBINATION AND PROPOSAL LESSON № 4 Topic. The structure and types of phrases by the type of subordinate relationship Purpose: to acquaint students with the material about different types of subordinate communication in phrases; to form the skills and abilities of parsing phrases; develop the ability to logically and consistently present theoretical material; foster the desire to gain new knowledge, skills of competent writing. Equipment: textbook, didactic material, flashcards, […].
Types of phrases by the way of expressing the main word Russian language – Russian language Syntax and punctuation Phrases Types of phrases by the way of expressing the main word 1. Nominal. 2. Verbs. 3. Adverbs.
FOLK CRAFTS. DECORATIVE ARTS Lesson 29. FOLK CRAFTS. DECORATIVE ARTS Deepening knowledge about folk crafts and decorative arts of Ukraine and Russia 176. Read proverbs and sayings. What theme are they united by? 1. Working hands do not know boredom. 2. Patience and work will grind everything. 3. The day is small for a good owner. Write down the statements from memory. 177. Consider photo illustrations. What is depicted on them? Shirt […].
The structure and types of phrases by the type of subordinate relationship (coordination, management, adjoining) LESSON № 6 Topic. The structure and types of phrases by the type of subordinate relationship (coordination, management, adherence) Purpose: to teach students to determine the types of subordinate communication in the phrase; develop their ability to use synonymous phrases in speech; cultivate kindness. Expected results: students characterize the type of syntactic connection, make up synonymous phrases; use them correctly in speech. Equipment: textbook, diagram, didactic material. […].
Types of one-part sentences with a leading predicate (generalized personal, impersonal) SIMPLE PROPOSAL LESSON № 26 Topic. Types of one-part sentences with the main predicate member (generalized personal, impersonal) Purpose: to teach to distinguish one-part sentences with the main predicate member (generalized personal, impersonal sentences), to determine the ways of expressing the predicate; develop the ability to distribute language material in accordance with the tasks; foster a conscientious attitude towards learning. Equipment: textbook, handout and didactic material. LESSON PROCESS Learning […].
ORGANIZATION OF THE WORKPLACE. RULES OF SAFE WORK IN PERFORMANCE OF LOCKSMITTING WORKS § 1. ORGANIZATION OF THE WORKPLACE. SAFE WORK RULES WHEN PERFORMING LOCKSMITTING WORKS 1. What tools and devices do you already know how to use? 2. Why do you think it is important to organize the workplace correctly when making products? 3. What house rules and safe work in the school workshop do you already know? Metal products in school workshops […].
Types of sentences for the purpose of the statement (narrative, interrogative, incentive). Emotional sentences (exclamation points). Interrogative sentences with a particle of li (ukr. Chi). Intonational formality of sentences. Logical stress. Punctuation marks at the end of a sentence LESSON № 63 Topic. Types of sentences for the purpose of the statement (narrative, interrogative, incentive). Emotional sentences (exclamation points). Interrogative sentences with a particle of li (ukr. Chi). Intonational formality of sentences. Logical stress. Punctuation marks at the end of a sentence Purpose: to teach to determine the type of sentence according to the purpose of the statement; teach the ability to build and correctly intonate simple sentences, taking into account the purpose of the statement and […].
DRILLING MACHINE CONTROL METHODS Section 3. Fundamentals of engineering, technology and design Topic 3.1. Mechanisms and machines. Drilling machine § 19. METHODS OF CONTROL OF THE DRILLING MACHINE 1. What are the main units of the drilling machine? 2. What type of machine does the drilling machine belong to? 3. What is the purpose of the wedge drive of the drilling machine? Work on a drilling machine begins with its preparation. Preparatory work includes […].
Methods of forming words Russian – Russian language Composition of a word Methods of forming words 1. Prefix (with a prefix): 2. Suffix (with a suffix): 3. Prefix-suffix (with the simultaneous attachment of a prefix and a suffix): 4. Nonfix ( by dropping the suffix): 5. Transition of words from one part of speech to another: 6. Addition of words, stems and their parts: 1) forest (adding stems); 2) […].
Types of one-piece sentences with a leading predicate (definite personal, indefinite personal) SIMPLE Sentence LESSON 25 Topic. Types of one-part sentences with the main predicate member (definitely personal, indefinitely personal) Purpose: to teach to distinguish one-part sentences with the main predicate member (definitely personal, indefinitely personal), to determine the ways of expressing the predicate; develop the ability to select language material in accordance with the assigned tasks; foster Patriot feelings. Equipment: textbook, handout and didactic material. LESSON PROCESS To believe firmly means […].
Verbs denoting different kinds of actions. We read in silence: we compose questions according to the text. We say: we use words denoting feelings, mental activity of a person 46. Verbs denoting various types of actions. We read in silence: we compose questions according to the text. We say: we use words denoting feelings, mental activity of a person 371. Write down the words, opening brackets and inserting missing letters. (Not) loved, (not) greeted, (not) yearning, (not) fell asleep, per.with poured, like (d, t) then, (not) liked it, maybe it could be , (not) tits, with de (ts, c) tva, from (sc, u) parts. 372. Read silently. Tell us what you learned about […].
Different Sandpaper Grits | and how to use them
FURNITURE CARE Section 4. Technology of household activities Topic 4.2. Housing hygiene § 27. FURNITURE CARE 1. What is the role of cleaning living quarters in a person’s life? 2. Why does health depend on the quality of cleaning? Justify the answer. Any living space has furniture designed for comfort and coziness. Cabinets, cabinets, chests of drawers and some other furniture belong to cabinet furniture (Fig. […].
An important parameter of sandpaper is not only the size of the grains, but also what material they are made of. They are usually made from the following abrasives:
- Silicon carbide.
Pomegranate-based sandpaper has sufficient softness and elasticity, which is important when processing embossed wood. This natural material seals the pores when rubbed, which further blocks the wood from getting wet if it has not been painted.
Silicon carbide is an excellent solution when grinding hard metal. It can also be used to remove old paint and adjust the shape of plastic parts..
Ceramic spraying is hard and rough. It is used for spraying on paper used in woodworking. Commercial long sanding belts for industrial machines are often ceramic coated. Ceramics cut quickly into wood and are highly wear resistant. The large contact area with the base ensures reliable adhesion, so the grains stay fixed longer, and the skin does not lose its properties even after prolonged use.
The skins, on the basis of which aluminum oxide spraying is used, is also used when working with wood. The peculiarity of this material is that when heated, the grains break like glass. As a result of hacking, new sharp edges are formed on them, which cut even more effectively into the surface to be treated. Thanks to this, such a skin does not lose its effectiveness for a long time..
The most expensive and effective are diamond-coated abrasives. This mineral is very hard, therefore it works equally effectively with both better quality steel and wood. The diamond is resistant to the influence of overheating, so its edges do not grind down during prolonged use without cooling. Such skins are rarely made, since the production is quite costly, and the sandpaper themselves are expensive, so it is more profitable to give preference to more budgetary counterparts. After diamond skins, in terms of efficiency, there are products with sputtering in the form of silicon carbide..
The most widespread and cheapest is paper coated with fused corundum. This substance is obtained by melting metal shavings in arc furnaces. For comparison, the hardness of this material is 4 times lower than that of diamond sandpaper..
The first is always indicated by the letter “P”. The number after indicates graininess.
For example: P400 is a well-known “zero”.
According to the grain size, sandpaper is divided into two large grades, fine-grained, starting from sandpaper-zero and coarse-grained.
Types of abrasives on a product for metal, wood and glass
Sandpaper, depending on the type of abrasive, is intended for use with the corresponding types of materials:
- Ordinary electrocorundum or aluminum oxide – are used for processing cast iron surfaces, as well as hardened and unhardened steel, and wood
- White electrocorundum – used for processing alloyed and heat-resistant steel
- Flint – silicon sandpaper allows processing wood, plywood and leather materials
- Silicon carbide – finishing of cast iron, aluminum, plastic, marble, granite, glass, wood and bronze
- Quartz – for processing ceramics and optical surfaces
- Glass – for processing wood, plywood, felt and felt
- Pomegranate – serves for grouting the surface of hard types of wood products
- Diamond – polishing of hard alloy and cast iron parts
- Elbor – for processing steel billets
Application of sandpaper depending on its grain size
Paper release form
And the difficulty is what?
The confusion is that the domestic marking on the skin can be made according to the new GOST of 2005 (focused on European standards) and according to the GOST of the 80s, approved by the Ministry of Machine-Tool and Tool Industry of the USSR.
The two categories of standards are reversed. In the old GOST 3647-80, a decrease in marking numbers meant a decrease in grain size. In the new GOST, the grain of the abrasive decreases, and the number in the marking, on the contrary, increases..
In addition, there is no unity among global manufacturers. USA and Canada, Europe and Turkey, Japan, China adhere to its own standard.
Cloth-based abrasive paper is more wear-resistant and more durable.
The fabric backing also provides great flexibility, making the fabric an indispensable backing for making ring sander belts..
Abrasive grit: classification
It is the grain size that is the main characteristic of the abrasive paper. Abrasive powder can have grains ranging in size from 3-5 to 1000 microns. The grain size determines the scope of application of the sanding paper. In the USSR, sanding paper was classified according to GOST 3647-80, and now in the Russian Federation – according to GOST R 52381-2005. The USA and Canada (ANSI), Japan (JIS) and China (GB2478) also have their own standards. The unified standard ISO 6344 (FEPA) operates in the international arena.
The Russian standard, like the international FEPA standard, denotes the grain size ascending by the letter P with a number that indicates the number of wires in the sieve per 1 square meter. inch. However, you should be aware that in a number of CIS countries the Soviet marking is preserved: the grain size is measured in microns, denoting it with the letter H with numbers. At the same time, the smallest sandpaper has, in addition to the letter H, the letter M with the corresponding numbers (they indicate the grain size in microns).
It should also be recalled that, for example, sandpaper for rough work, having a grain size of 800-1000 microns, is designated P22 according to the FEPA standard, and 80-N according to the Russian GOST 3647-80. Accordingly, sandpaper with a grain of 3-5 microns according to the international standard FEPA is designated P2500, and according to GOST 3647-80 – M5 / H-00 (by the way, it is because of these zeros that the colloquial name “zero” appeared). Well, sanding paper with medium grains (125-160 microns) has the designations P100 (FEPA) and 16-H (GOST 3647-80).
Sandpaper is the most common abrasive material, consisting of a cloth or paper backing and a layer of powdered abrasive (grain). Used for grinding various products. Sandpaper is an invention of the English entrepreneur John Oakey, who lived in the 19th century and who first organized its industrial production. However, it has been known since the 13th century. In China, for example, it was made of parchment, which was covered with a layer of glue and sprinkled with a layer of sand, hard seeds or crushed shells.
Abrasive powder: types and features
Nowadays, for the production of abrasive powder, electrocorundum and carborundum are most often used, less often – artificial diamond, garnet and elbor.
Electrocorundum. Its grains withstand strong pressure and have sharp edges at the break, giving the powder a high cutting ability. Produced by smelting reduction from a charge, which is a mixture of iron shavings, low ash carbon filler and bauxite agglomerate. Alloy additives can be added to increase the strength and abrasion of the fused alumina.
Carbocorundum. It has unique properties: it is more fragile than fused alumina, but surpasses it in hardness, which is why the crystals constantly split during operation and form new cutting edges. This allows silicon carbide to maintain its working ability for a long time and protect the sandpaper from clogging, so this type of tool is often used for surface finishing of plastic and glass products, as well as for finishing metal surfaces. Carbocorundum is produced in Acheson’s electric furnace by sintering silica and graphite.
Garnet. A relatively soft mineral of natural origin with a hardness of 6.5-7.5 Mohs units. Accordingly, pomegranate grit sandpaper is used when processing soft materials (mainly wood). It has one important property: with the same grain size compared to sandpaper made from other abrasives, it gives a smoother surface.
Diamond and Elbor. These are expensive abrasives, so abrasive paper with them is quite rare. Possess unique properties. Diamond has the highest hardness, and elbor is only slightly inferior to it in this characteristic, but it wins over diamond in its resistance to high temperatures..
Marking: decoding rules
Marking is applied to the abrasive paper with paint on the reverse side. Here is an example of decoding one of the markings (all designations have a standard one – L1E620 together with 50P215A25-NMA and a mention of the corresponding GOST):
L – sanding paper sheet (if the sanding paper is in rolls, the letter is absent).
1 – type of paper (1 – for processing products from low hardness materials, 2 – from metals).
E – abrasive powder applied electrostatically.
620 – size (width and length), for sheet skin – in mm, for skin in rolls – width in mm, length in m.
P2 – base (paper – 0-200; moisture-resistant paper – L1, L2, M; non-moisture-resistant paper – P1-P11; twill fabric – C1, C1G and S2G, U1 and U2, U1G and U2G; semi-duplex fabric – P).
15A – grade of electrocorundum (normal – 15A; white – 24A, 25A; mono-corundum – 43A, 45A; black silicon carbide – 53C-55C; green silicon carbide – 62C, 63C; glass – 71St; flint – 81Kr).
25 – size in microns of the main fraction of the abrasive (micro-grinding powders – M63-M3).
N – the main fraction of the abrasive powder in percent (D – not less than 41%; N – not less than 45; P – not less than 55; B – not less than 60).
M – type of adhesive layer (M – abrasive fixed with skin glue; C – synthetic; K – combined bond (MS); SFC – phenol-formaldehyde resin; YAN-15 – amber varnish).
A – indicator of wear resistance in percent (B – no more than 3%; A – no more than 0.5; B – no more than 2).
Abrasive base: types and properties
Sanding paper is made on a cloth, less often on a paper basis. The advantage of the latter is the low price, the ability to apply grain of fine fractions, the absence of stretching during operation. For the fabric base, cotton and polyester are used (they are saturated with a special resin that increases the strength and moisture resistance of the skin). Has two drawbacks – a higher price in relation to and a tendency to stretch when working.
The sandpaper can also have a fiber base or be combined. Fiber is a denser and harder material with low moisture resistance, which is why this type of sandpaper is used to a limited extent..
Abrasive application methods and the scope of application of abrasives
The abrasive powder is applied to the substrate by the following methods:
open and half-open (abrasive powder is applied on 40-60% of the base);
closed (powder covers the entire surface).
The paper created by the first method is convenient when working with loose and non-solid materials (putty, wood, fibrous surfaces, etc.). Closed-grain sanding paper is used for finishing surfaces made of metal, dense wood and plastic.
They work with abrasive paper both manually and mechanically, using vibration, surface grinding, eccentric, belt and other machines. In addition to sheets and rolls, sanding paper can be produced as special tools for special tasks..
Abrasive paper is not the material of choice for the price. They focus on the tasks that need to be solved, therefore, they look first of all at the type of base and grain sizes, and then at other characteristics indicated in the marking.