3D Printing
3D Printing Tips and Tricks
钛合金3D打印
CandyFab printing sugar
成本100元,制作3d打印机
3D打印金屬材料之鈦及鈦合金材料
Easy 3d Printing
3D Projection Pyramid in 10 min from Clear Plastic Sheet
ENGINEERING
3Dprint
3D打印系统
个人3D打印
3D打印革命
杭州3D打印
3D打印机开源
3D打印服务
3D打印网
OpenSCAD
Tinkercad
engineering.com
GrabCAD
3D
3D Printing Software Tools
3D Extruded clay
Liquid 3D
Carbon3D
Liquid Interface
Speeds-up 3D
Carbon3d Clip
直接金屬激光燒結
Direct metal laser sintering
Software
3D Models
3D Models
Archive 3D
3dprint
3dprintPrice
Free3dModel
3D Model
3Dmodeling
3D模型库
华曙
3D Warehouse
Cad Library
3D Library
HK 3D-Print Service
Free 3D Model
自我繁殖机器
Reprap
ReprapBlog
Pololu
Reprap StepStick
3D打印简介
Twente 3D Pwdr
Formlabs
B3dge
low cost 3D metal printer
开源3D打印
金属激光烧结
IML工艺
THINGIVERSE
安帅科技
广州电子技术公司
北京朝日
Printing
三维曲面印刷
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精细卷对卷印刷技术
水转印技术
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水轉印效果
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水轉印技術
Hydrographics
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water-transfer-printing
LED Printers
Digital Print Preservation Portal
水溶膜
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水容性载体
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水溶膜用途
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现状 展望
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绣花水溶膜
Paint Tech
顏料
发泡油墨
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丙烯颜料
4 Types of Acrylic Paint
♦油漆
丙烯颜料
丙烯颜料又称为塑胶彩或压克力颜料, 英语为“acrylic”,发明于1950年代,是颜料粉调和制成的。
丙烯颜料可以用水或稀释剂稀释,但在干后迅速失去可溶性,不再溶于水。
且不易褪色,持久性较好。
另外,丙烯颜料也是大多数人学习油画前的替代品,因为两者的成品及技法有不少类似之处。
丙烯颜料绘画技法又可分为类似水彩画的透明技法以及类似油画的不透明技法两种运用。
在压克力颜料中加入清水,则可让颜料呈现透明似水彩的状态。
若只调和微量的水分或者不加入水分,颜料则不透明,可厚实堆叠出类似油画的效果。
在颜料的变化上,也有加入增厚剂或增光剂,提升颜料的光泽度及透明度。
毒性
丙烯颜料有轻微毒性。
清除方法
立刻用清水或肥皂水搓洗。
颜料干后,可用清水长时间浸泡,或于80摄氏度左右的热水浸泡后再搓洗。
溶于汽油。
Acrylic paint is a fast-drying paint made of pigment suspended in acrylic polymer emulsion.
Acrylic paints are water-soluble, but become water-resistant when dry.
Depending on how much the paint is diluted with water, or modified with acrylic gels, mediums, or pastes, the finished acrylic painting can resemble a watercolor, a gouache or an oil painting, or have its own unique characteristics not attainable with other media.
Painting with acrylics
Before the 19th century, artists mixed their own paints, which allowed them to achieve the desired color and thickness, and to control the use of fillers, if any.
While suitable media and raw pigments are available for the individual production of acrylic paint, hand mixing may not be practical because of the fast drying time and other technical issues, such as the necessity to combine several polymers, as well as surfactants, plasticizers, dispersants, defoamers and stabilisers in the correct amounts and order.
Acrylic painters can modify the appearance, hardness, flexibility, texture, and other characteristics of the paint surface by using acrylic mediums or simply by adding water.
Watercolor and oil painters also use various mediums, but the range of acrylic mediums is much greater.
Acrylics have the ability to bond to many different surfaces, and mediums can be used to modify their binding characteristics.
Acrylics can be used on paper, canvas and a range of other materials, however their use on engineered woods such as medium-density fiberboard can be problematic because of the porous nature of those surfaces.
In these cases it is recommended that the surface first be sealed with an appropriate sealer.
Acrylics can be applied in thin layers or washes to create effects that resemble watercolors and other water-based mediums.
They can also be used to build thick layers of paint—gel and molding paste are sometimes used to create paintings with relief features.
Acrylic paints are also used in hobbies such as trains, cars, houses, DIY projects, and human models.
People who make such models use acrylic paint to build facial features on dolls, or raised details on other types of models.
Wet acrylic paint is easily removed from paintbrushes and skin with water, whereas oil paints require the use of a hydrocarbon.
Acrylic paints are the most common paints used in grattage, a surrealist technique that became popular with the advent of acrylic paint.
Acrylics are used for this purpose because they easily scrape or peel from a surface.
Painting techniques
Acrylic artists' paints may be thinned with water or acrylic medium and used as washes in the manner of watercolor paints, but unlike watercolor the washes are not rehydratable once dry.
For this reason, acrylics do not lend themselves to the color lifting techniques of gum arabic-based watercolor paints.
Instead, the paint is applied in layers, sometimes diluting with water or acrylic medium to allow layers underneath to partially show through.
Using an acrylic medium gives the paint more of a rich and glossy appearance, whereas using water makes the paint look more like watercolor and have a matte finish.
Acrylic paints with gloss or matte finishes are common, although a satin (semi-matte) sheen is most common.
Some brands exhibit a range of finishes (e.g. heavy-body paints from Golden, Liquitex, Winsor & Newton and Daler-Rowney); Politec acrylics are fully matte. As with oils, pigment amounts and particle size or shape can affect the paint sheen.
Matting agents can also be added during manufacture to dull the finish.
If desired, the artist can mix different media with their paints and use topcoats or varnishes to alter or unify sheen.
When dry, acrylic paint is generally non-removable from a solid surface if it adheres to the surface.
Water or mild solvents do not re-solubilize it, although isopropyl alcohol can lift some fresh paint films off.
Toluene and acetone can remove paint films, but they do not lift paint stains very well and are not selective.
The use of a solvent to remove paint may result in removal of all of the paint layers (acrylic gesso, et cetera).
Oils and warm, soapy water can remove acrylic paint from skin.
Acrylic paint can be removed from non-porus plastic surfaces, such as miniatures or models using certain cleaning products such as Dettol (containing chloroxylenol 4.8% v/w)
An acrylic sizing should be used to prime canvas in preparation for painting with acrylic paints, to prevent Support Induced Discoloration (SID).
Acrylic paint contains surfactants that can pull up discoloration from a raw canvas, especially in transparent glazed or translucent gelled areas.
Gesso alone will not stop SID; a sizing must be applied before using a gesso.
The viscosity of acrylic can be successfully reduced by using suitable extenders that maintain the integrity of the paint film.
There are retarders to slow drying and extend workability time, and flow releases to increase color-blending ability.
thermoplastic-polymer
Polyethylene is a thermoplastic resin, which means an item made with the material can be recycled, melted down and reformed into another shape.
Polyurethane, on the other hand, is a thermoset resin, meaning that it has two parts mixed together to form a chemical chain.
Once polyurethane is cured, the process can’t be undone.
This means that something made of polyurethane can’t be melted down and reformed into a different item.
What is Polyurethane Foam?
Polyurethane foam is one of the four basic types of products that can be made from raw, liquid polyurethane.
They are comprised of two chemicals which, when mixed and heated, form liquid polyurethane prior to being further processed.
These chemicals are polyol, a type of complex alcohol, and diisocyanate, a petroleum byproduct that reacts strongly with alcohol.
By combining the two, a stable long-chain molecule is formed.
It's a polymer, or plastic, known as urethane.
What is Polyurethane Foam Used For?
Polyurethane foam is used primarily for bedding and furniture stuffing.
It's hypoallergenic, nontoxic and does not degrade over time.
This means that cushions filled with it will always regain their shape, no matter what punishment they're put through.
Foam beds are also becoming popular.
The solid layer of foam molds to fit the body.
Packing peanuts and foam inserts are also used by shipping companies across the world.
How is Polyurethane Foam Made?
Once the two ingredients have been combined to form hot liquid polyurethane, they are passed down through a pipe into a nozzle head.
Beneath the head is a series of rollers upon which waxed paper passes by.
The nozzle jets a fine spray of hot liquid over the waxed paper, mixing with blasts of carbon dioxide coming from another nozzle.
This causes the polyurethane to expand as it moves down the conveyor belt, forming a foam strip.
The edges of the foam are trimmed and compressed to ensure it retains a viable shape.
The foam is comprised of an untold number of tiny gas bubbles trapped in the polyurethane.
Unless the gas is released, the foam will take on the consistency of a rock.
So, the foam passes beneath a series of heat lamps.
It dries the foam and causes the bubbles to expand, then burst, leaving a completed spongy porous material behind.
Urethane Vs. Polyurethane
Although the terms "urethane" and "polyurethane" are often used interchangeably, these are two distinctly different compounds.
Urethane
Urethane is a crystalline compound with the chemical formula C3 H7 NO2.
It is an ester of carbonic acid.
Polyurethane
Polyurethane is called such because it is composed of multiple, or “poly,” urethane units.
The urethane units are joined by a chemical reaction called polymerization.
Properties
Urethane is flexible and malleable, making it ideal for objects that have different shapes and forms, and it is used in liquid form.
Polyurethane, on the other hand, is stiff and rigid and is ideal for firmer items, with many advantages over natural rubber.
Urethane Uses
Many insecticides, veterinary medicines and pharmaceuticals contain different amounts of urethane.
The compound is also used as a solvent.
Some plastics are formed of urethane.
Polyurethane Uses
Polyurethane is used for solid materials such as shoes and foams.
Some types of polyurethane are also mixed in paints for a long-lasting coating.
Toxicity
Urethane is toxic to small animals.
People who take pharmaceuticals with urethane often experience nausea as a side effect.
Polyurethane, on the other hand, biodegrades very slowly and generally poses a low toxic risk.
What Is a Polymer?
A polymer is simply a material composed of many repeated units called monomers that link together into chains or branches.
Some polymers like starch, cellulose and rubber occur naturally while others like polyester, nylon and plastic are synthetic.
What Makes Thermoplastic Polymers Special?
The monomers that make up thermoplastic polymers come together via electrical bonds called van der Waals forces that weakly attract neutral molecules to each other.
These repeating units arrange themselves in such a way that thermoplastic polymer molecules look like many strands of pearls mixed together.
Because their bonds are weak, thermoplastic polymers readily soften when heated, allowing manufacturers to mold them into a wide range of shapes, then resoften them and mold them again.
This ability to reuse thermoplastic polymers indefinitely means they are highly recyclable.
Other benefits of these polymers include excellent strength and a tendency to resist shrinking.
On the other hand, thermoplastic polymers do have a few drawbacks, including high production costs and the fact they melt easily, which renders them inappropriate for some high temperature applications.
What Are Some Common Thermoplastic Polymers?
There are actually many types of thermoplastic polymers, which are unique in form and function.
Manufacturers often use high pressure polyethylene to encapsulate rigid objects like electrical equipment.
Low pressure polyethylene is very elastic and ideal for insulating electrical cables.
Polyamide is most commonly associated with the production of ropes and belts.
Perhaps the most readily recognizable thermoplastic polymer is polyvinyl chloride, or PVC, which readily molds into pipes, containers and insulation materials.
Finally, some adhesives are thermoplastic polymers, including acrylates, cyanoacrylates and epoxy.
While thermoplastic polymers come in a wide range of formats and serve many unique purposes, the basic features of these materials remains the same: high versatility and recyclability.
When it comes to chemistry applications in the real world, you would be hard-pressed to find a better example than the production of plastics, including thermoplastic polymers.
creative wall painting
Chemicals in Dry-Erase Markers
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白板笔墨水
聚酯漆
古象彩色聚酯漆
荧光剂
長效型夜光漆
红外线和紫外线及其应用
釉
釉藥是什麼
釉藥與玻璃成分相近,
釉藥需燒附在坯體上,玻璃則可成形為獨立個體;
然而釉藥可增加陶瓷器的裝飾與保護效果,
得以盛裝水、食物或製成衛浴用品,
防止液體滲漏,讓表面容易清洗,
且由於釉色變化多端,讓陶瓷呈現多采多姿的面貌。
一般陶藝釉藥是由多種粉末原料組成,
如臺灣常見的長石原料為:日化長石、釜戶長石、澳洲長石、霞正長石...等,
再與其他原料,如石英、高嶺土、碳酸鋇、氧化鋅、石灰石、骨灰...等,
也會混和金屬氧化物:氧化鐵、氧化猛、碳酸銅、氧化鈷...等,
依重量比例調成,最後加入適量的水呈現液體狀態後,
使用浸、噴、刷、淋、彩繪等施釉技法,
讓坯體表面堆疊至適當的厚度層,
再經由每種釉藥適合的溫度燒成。
陶藝釉藥以溫度可區分為四個區塊
低溫釉 900~980℃
低中溫釉 1000~1160℃
中溫釉 1160~1280℃
高溫釉 1300以上℃,
通常鮮艷的釉色在低溫較容易保留,
但也較易釋放出金屬物質,
然而1200℃以上的釉藥較穩定,不會釋放金屬物質,
毛細孔變小,也不易沾黏汙垢。
柴燒窯內的火焰與坯體狀態,大約接近1000度。
影響陶藝釉藥的燒成氣氛
氧化燒
燒成時窯內充滿氧氣(空氣)的條件下燃燒加熱。
釉色穩定。例:結晶、銅綠、鐵紅...等釉色。
一般普通電窯(單純電熱絲加熱)。
還原燒
燒成時讓窯內氧氣(空氣)供應不足的條件下燃燒加熱,
轉而進入坯體與釉藥尋找氧氣燃燒。
釉色富變化,但較不易控制。例:青瓷、銅紅、鈞窯...等釉色。
瓦斯窯、柴窯、氧化還原兩用電窯。
瓦斯窯使用瓦斯燃燒,可看到火焰,控制空氣、壓力、氣壓...等狀態,來達到還原的效果。
備註:一般區分為氧化燒與還原燒,但另有中性氣氛,需視釉藥來決定。
多采多姿的陶瓷釉藥
《釉藥學》。臺北:鶯歌陶瓷博物館。
材料
聚醚醚酮
聚醚醚酮
Methods to recover the elasticity of silicone rubber
Heat treatment: Silicone rubber can lose its elasticity over time due to exposure to extreme temperatures or environmental factors.
By subjecting the rubber to controlled heat, you can restore its elasticity.
Place the silicone rubber object in an oven set at a low temperature, typically around 150-200 degrees Celsius (300-390 degrees Fahrenheit), for a specific period of time.
This process, known as heat treatment or annealing, helps to relax the polymer chains and restore the material's elasticity.
Be sure to consult the manufacturer's guidelines or perform a small test before exposing the entire object to heat.
Compression molding: Silicone rubber can be restored by subjecting it to compression molding.
This method involves applying pressure to the rubber to reshape and reform its structure.
Place the silicone rubber object between two heated plates or molds and apply pressure.
The heat softens the material, allowing it to flow and regain its original shape.
This process can help eliminate any deformations or stresses that may have caused the loss of elasticity.
Silicone rejuvenation products: There are silicone rejuvenation products available on the market that can help restore the elasticity of silicone rubber.
These products typically contain silicone oils or treatments that penetrate the rubber surface and replenish its lost elasticity.
Follow the instructions provided with the product for proper application and curing time.
Mechanical stretching: Gently stretching the silicone rubber can help restore its elasticity to some extent.
Take the rubber object and stretch it slowly and evenly in different directions.
This process helps realign the polymer chains and improves the material's elasticity.
However, be cautious not to overstretch the rubber, as it may lead to permanent deformation or tearing.
Remember to consider the specific properties and composition of the silicone rubber you are working with, as different formulations may require different approaches for recovery.
If you have valuable or critical silicone rubber components, it is advisable to consult the manufacturer or an expert in the field for guidance on the best method to restore elasticity.