FORUM:organizacja EVENTÓW - konferencji, szkoleń, imprez biznesowych i rozrywkowych
 
powrót do strony www.konferencje.com
 FAQFAQ   SzukajSzukaj   GrupyGrupy   RejestracjaRejestracja   ProfilProfil   Zaloguj się, by sprawdzić wiadomościZaloguj się, by sprawdzić wiadomości   ZalogujZaloguj 
Chemical foamed injection molding

 
Napisz nowy temat   Odpowiedz do tematu    Forum FORUM konferencje.com Strona Główna -> O obiektach:
Zobacz poprzedni temat :: Zobacz następny temat  
Autor Wiadomość
Juniper



Dołączył: 29 Sie 2019
Posty: 134

PostWysłany: Sob Wrz 28, 2019 1:18 pm    Temat postu: Chemical foamed injection molding Odpowiedz z cytatem

Plastic pellets mixed with a gas generating chemical agent is fed through a container into a rotating screw whose spiral shape moves the pellet forward through a heated chamber. The mixture is heated gradually blending into a homogeneous plastic melt. The chemical process starts and microscopic bubbles begin to emerge.

The mixed mass is then forced into a mold as the entire screw is pushed forward by an applied pressing force. The small gas bubbles grows larger during cooling and thus creates a porous interior while the surface is solid. The mold is opened and finally the part is removed by means of ejectors .
Powrót do góry
Zobacz profil autora Wyślij prywatną wiadomość
Zoe



Dołączył: 06 Wrz 2019
Posty: 130

PostWysłany: Sob Wrz 28, 2019 1:18 pm    Temat postu: Odpowiedz z cytatem

The general rule of thumb for injection speed with CFAs is faster is better. Often an accumulator will be used to accomplish this, as in the case of structural-foam molding. Faster injection allows for uniform expansion of the foaming agent. But it can be counterproductive in cases where the mold is not adequately vented. Reducing clamp tonnage is a proven solution in some of these instances. High velocities at the beginning of the shot, followed by reduced shot speed toward the end of injection has been noted to work in other situations where venting and part geometry were limiting factors.
Powrót do góry
Zobacz profil autora Wyślij prywatną wiadomość
gdhsdhe



Dołączył: 07 Wrz 2019
Posty: 122

PostWysłany: Sob Wrz 28, 2019 1:19 pm    Temat postu: Odpowiedz z cytatem

Zoe napisał:
The general rule of thumb for injection speed with CFAs is faster is better. Often an accumulator will be used to accomplish this, as in the case of structural-foam molding. Faster injection allows for uniform expansion of the foaming agent. But it can be counterproductive in cases where the mold is not adequately vented. Reducing clamp tonnage is a proven solution in some of these instances. High velocities at the beginning of the shot, followed by reduced shot speed toward the end of injection has been noted to work in other situations where venting and part geometry were limiting factors.




Post-expansion or post-blowing of parts after demolding can occur for a number of reasons, including inadequate cooling and excessive dose of foaming agent. If increased cooling time or a reduction in CFA dose does not work, the shot size may be too large.


Rough surfaces or splayed appearances are associated with parts foamed for weight reduction on standard high- and low-pressure injection machines. Reducing the amount of foaming agent, increasing the injection rate and pressure, and even increasing the mold temperature are all ways to try to improve the surface appearance of the part.
Powrót do góry
Zobacz profil autora Wyślij prywatną wiadomość
Juniper



Dołączył: 29 Sie 2019
Posty: 134

PostWysłany: Sob Wrz 28, 2019 1:19 pm    Temat postu: Odpowiedz z cytatem

Most plastics are based on the carbon atom. Silicones, which are based on the silicon atom, are an exception. The carbon atom can link to other atoms with up to four chemical bonds. When all of the bonds are to other carbon atoms, diamonds or graphite or carbon black soot may result. For plastics the carbon atoms are also connected to the aforementioned hydrogen, oxygen, nitrogen, chlorine, or sulfur. When the connections of atoms result in long chains, like pearls on a string of pearls, the polymer is called a thermoplastic. Thermoplastics are characterized by being meltable. The thermoplastics all have repeat units, the smallest section of the chain that is identical. We call these repeat units unit cells. The vast majority of plastics, about 92%, are thermoplastics1.
Powrót do góry
Zobacz profil autora Wyślij prywatną wiadomość
beachhandshake



Dołączył: 17 Cze 2019
Posty: 14

PostWysłany: Sob Wrz 28, 2019 1:20 pm    Temat postu: Odpowiedz z cytatem

MK-CR series release agent is water-based concrete mold release, good demolding performance, harmless, and easy to clean, mainly used in aluminum, steel, resin, ABS plastic molds, woods, and other material molds concrete formwork demolding process.Leader of Mold Release Agent Manufacturers with over 20 Years Experience. High Technology& Formula From Japan to Provide The Highest Quality Products.If you want to know more details please visit here meiyahg.com
Powrót do góry
Zobacz profil autora Wyślij prywatną wiadomość
Zoe



Dołączył: 06 Wrz 2019
Posty: 130

PostWysłany: Sob Wrz 28, 2019 1:20 pm    Temat postu: Odpowiedz z cytatem

The groups of atoms that are used to make unit cells are called monomers. For some plastics, such as polyethylene, the repeat unit can be just one carbon atom and two hydrogen atoms. For other plastics, such as nylons, the repeat unit can involve 38 or more atoms. When we combine monomers, we generate polymers or plastics. Raw materials form monomers that can be or are used to form unit cells. Monomers are used form polymers or plastics
Powrót do góry
Zobacz profil autora Wyślij prywatną wiadomość
gdhsdhe



Dołączył: 07 Wrz 2019
Posty: 122

PostWysłany: Sob Wrz 28, 2019 1:20 pm    Temat postu: Odpowiedz z cytatem

Zoe napisał:
The groups of atoms that are used to make unit cells are called monomers. For some plastics, such as polyethylene, the repeat unit can be just one carbon atom and two hydrogen atoms. For other plastics, such as nylons, the repeat unit can involve 38 or more atoms. When we combine monomers, we generate polymers or plastics. Raw materials form monomers that can be or are used to form unit cells. Monomers are used form polymers or plastics




When the connection of the carbon atoms forms two and three-dimensional networks instead of one-dimension chains, the polymer will be a thermoset plastic. Thermoset plastics are characterized by not being meltable. Thermoset plastics, such as epoxy adhesives or unsaturated polyester boat hulls and bathtubs or the phenolic adhesives used to make plywood, are created by the user mixing two chemicals and immediately using the mixture before the plastic “sets up” or cures.
Powrót do góry
Zobacz profil autora Wyślij prywatną wiadomość
Wyświetl posty z ostatnich:   
Napisz nowy temat   Odpowiedz do tematu    Forum FORUM konferencje.com Strona Główna -> O obiektach: Wszystkie czasy w strefie CET (Europa)
Strona 1 z 1

 
Skocz do:  
Nie możesz pisać nowych tematów
Nie możesz odpowiadać w tematach
Nie możesz zmieniać swoich postów
Nie możesz usuwać swoich postów
Nie możesz głosować w ankietach


Powered by phpBB © 2001, 2005 phpBB Group