Posts Tagged ‘toy’

He walked into the room to deliver the news that the company was going to be looking at the possibility of outsourcing parts of their it services

He walked into the room to deliver the news that the company was going to be looking at the possibility of outsourcing parts of their IT services. It was actually a part of their database management that IT hated and openly talked about hating. So he knew they would be glad to hear that the company would consider outsourcing it. He walked into the room, delivered his news, and was soon flooded with the resignations from his top talent.

What happened?

Another CEO wanted to get closer to all of the employees. He devised an internal message board where he could post all the news of what was going on. He knew that an informed employee is a happy employee and better able to do her job. He posted news about the company selling off some of their buildings and consolidating employees to their remaining buildings. Pandemonium broke out that day and production declined as the employees all wondered, “what is going to happen to us? Is the company losing money? Why would they sell their buildings?” Even though these buildings were like ghost towns with low occupancy.

In each of these scenarios the intent was good. Management was trying to deliver to employees what they thought they wanted. In both situations it backfired and in one case, with devastating effects as they lost their top talent.

There is a point to middle management and I am still baffled by companies that don’t get it. They believe that the new model of sharing information down to all levels is what will bring power to their company. They believe it will empower employees. The reality is that it most often baffles employees and creates a bigger rift between management and employees as well as causes wasted time answering unnecessary questions.

The new model of sharing often reduces senior management to crisis and reactive management and immobilizes the company. People forget that EACH role in the company plays a significant part and each role in the company needs the EXACT tools and information that they need to do their job—not any more and not any less.

To simplify this, let’s look at it in relation to a parent and child. Now please note that I am not saying that employees have the intelligence of a child or should be treated like a child. What I am saying is that they each have a specific role in the family and we should NOT confuse that. If every employee had the skills and tools to be a manager than they would be. But let’s face it, many don’t. And many don’t want to develop them either. They want the security of knowing the hours they need to work to get their paycheck period.

Let’s take the building example and look at it from the parent/child perspective. How do you think the child would react if the parents just came home and said, “We are selling our house and moving”? My guess is the child would be full of questions as the child tries to discover how this new information affects HIS WORLD. He may ask,” where are we moving to? Why are we moving? When will we be moving? Can I still see my same friends? Will I go to the same school? What will my room look like? Will I still have my own room? Where will my toys go? Can I bring my toys?” The parents will be inundated with 101 questions and they had better be prepared for them.

Now imagine what happens to the child if the parents say, “we don’t know. We just know we are selling our house.” The child is left to sort this all out on its own, draw their own conclusions, and pacify their fears. In this situation most people will go to the worse case scenario and panic.

The role the parents play is to PUT the information in to a CONTEXT that the child can understand. The error most management makes is to believe that their role is to DISPENSE information. That thinking will get you in trouble again and again.

It is the child’s role to think about everything they hear and filter it through their understanding of the information at that point and time. They probably can’t project out and understand Mom and Dad’s situation at that time. A job promotion, job transfer, or a layoff is difficult for them to grasp how it will change the family. For many kids, a layoff means Mom or Dad will be home more often. They have a hard time seeing how that could be a bad thing.

Now let me get back to middle management’s role in all of this. Senior management’s role is to visualize the future and push the company in new directions. Employees are the ones that actually do the work that makes the vision happen. Middle management plays the critical role of balancing the two and sharing senior management’s perspective with employees and vice versa. Middle management needs to be the one that employees can easily go to with questions, ideas and clarification. Without this important segment, employees either go to each other or bog senior management down with so many questions that senior management never gets to visualize and work on the future.

So what can you do about this?

Here are some quick tips on making sure that what you say is what is being heard:

  1. Think about what you are going to share from the other person’s perspective. How may they react to this information? What are their concerns and issues? How does this affect their world?
  2. Think about what medium you will use to share the information. Does it need to be face to face? Via video? Via video conferencing? Via the Message board? In order to determine this you need to know what you want the receiver to do with the information you are sharing.

Let’s go back to the first two examples I shared with you. With the IT department, the manager should have approached the group with the IDEA of outsourcing rather than just telling them that they were going to be doing it. That way, if employees complained that they didn’t think it should be outsourced, he could have directly challenged them on how they complain about managing the database and asked them how to effectively solve the issue.

With the building sale, simply adding on WHY they were selling the buildings and HOW it would positively affect the employees would have alleviated all problems.

There is a big difference between “we would like to announce that we have successfully negotiated the sale of two of our buildings on Dogmat campus. We will be consolidating all employees from those two buildings to our existing buildings”

And “In our efforts to always invest our money in our biggest asset-our employees- we have successfully negotiated the sale of our two low use buildings on Dogmat campus. Each of these buildings was less than 30% occupied and we were spending a lot of money maintaining unnecessary space. On top of that our other buildings are only at about 60% capacity. We will be moving all employees from these two buildings over to our existing buildings. There will be no job losses and this is not a move that signifies loss of growth. Instead it exemplifies our desire to keep our company on the cutting edge by keeping our capacity up and freeing our resources to continue our growth.”

The second way, although longer, answers key employee questions, calms nerves, and allows employees to focus on their work rather than on how this will affect their work.

Look at all of your communication from employee meetings to customer meetings to emails. Are you always thinking about the context of how you want your message received or are you merely trying to get your message out? Changing this one thing in your organization can have a dramatic impact on your company.

Blackberries and wifi and blogs (oh my

Blackberries and Wifi and blogs (oh my!). And your list likely goes on – email, IM’s, forwarding your phone number, wireless everything and 24 hour news channels. While it might be trite, we truly live in a 24/7 world.

Many of us didn’t grow up in a world quite like it is now – with the plethora of options for being connected, getting information and communicating. It wasn’t that many years ago when email and cell phones were new. Now a cell phone that connects to your email is old news!

The challenges of a 24/7 world are many, but as a leader there are four that are especially important to consider – both as an individual and in your role as a leader.

•    We have the option of always being connected.
•    We are awash in information.
•    We have too many sources of information to choose from.
•    Many people are increasingly addicted to all of it.

One crucial step to thriving in any situation is to identify and understand the challenges you face, and then identify ways to overcome, benefit from or eliminate those challenges. The ideas that follow are meant to help you do all three of these things.

Your Seven Ideas

Remember that these ideas about thriving, not merely surviving. This may mean that one or more of them is a bit more radical than you have considered or even think prudent. While you have to use your own judgment, I encourage you to do more than consider these ideas – but actually try them!

•    Manage your expectations of yourself. How much time do you want/need/have to be a connected info-holic? (Please note that these are three different questions – ask yourself all of them). Consider your answers carefully, and then make choices about your own expectations of yourself in an informed way.
•    Manage your expectations of others. As a leader you may choose to be connected and/or be on your computer at all times of the day or night. Unless you have a conversation with your team, they likely will begin to model your behavior. Maybe you choose to do email or send links to ideas you find at an odd hour, that’s fine, but you need to explicitly tell others what your expectations are for them. Let them know that “just because I’m online at 5 am doesn’t mean you need to be” or whatever is appropriate in your situation.
•    Turn off Tuesday afternoons. Face-to-face communication and the phone are amazing communication tools, and sometimes you will get more creative work done if the TV or web browser or email inbox is closed for awhile. Whether you pick Tuesday afternoons, Friday mornings, or whatever, consider a time during the work week when you disconnect from your toys and tools – and if you are a leader to have others do it as well. Personal experience and a variety of organizational experiments show that productivity may go up dramatically during these times.
•    Find information sources and tools that work for you. Focus primarily on the tools that work for you. Use them appropriately and focus your attention on them.
•    Turn off at night. At least one night a week (preferably more often) turn off the cell phone and don’t open the computer. If you find yourself lost without the computer open, you need this advice the most. If you really want to be reading and/or learning, open a book. Encourage your team to do this too – especially if you find yourself getting messages from them at all hours of the night.
•    Chill out and think. This idea addresses all four challenges mentioned above. If you remember what it was like before Web 2.0, interactive cell phones and more, you know that you could still get real work done. If you don’t remember or weren’t alive yet, trust me, you can get real work done. This idea is to just relax a little bit. When you are disconnected and unplugged be good with that. You don’t have to have your Bluetooth headset on during dinner, and you don’t have to take (or make) a phone call while in a public (or private) restroom. Relax a little. Use your disconnected time to think, rather than react to your technology.
•    You can’t do everything (so don’t try). Even if you are really wired to technology, and even if you love it, know that you can’t know everything about everything, because everything is so much bigger than it used to be. There will always be one more video site, cell phone option, all news blog or website. Be OK with that and refer back to idea #4.

A final note. A smart friend of mine called as I was writing this article and reminded me that some leaders are on the other end of this spectrum – either anti-technology or at least not challenged by these issues. If this is you, you need to recognize that many of your team could use the ideas above. And maybe you need to be a little more open minded to learn some of the benefits they are gaining in this 24/7 connected world – without falling into the their traps.

Potential Pointer: The communication and information options that are available to you in our 24/7 world are amazing! Always remember those options are tools designed to serve your needs, not make you a slave to them.

Tag:china toys

Tag:china toys?Children’s Tricycle
From:http://www.buy-china-toys.com/

With control bar
Small basket in front
Footrest for little children
One tricycle with two seats in front and at back
Movable canopy
Three pieces/carton
Size: 82 x 50 x 36cm
Gross weight: 21kg
Net weight: 20kg
460 pieces/40-foot HQ container
325 pieces/40-foot GP container
190 pieces/20-foot GP container
About Zhejiang ZEC Group
Zhejiang ZEC Group was founded in 1984 and engaged in the manufacturing and marketing of hardware, tools, electronics, garments, textiles, auto accessories and parts. Presently we’re a supplier for more than 200 customers over 30 countries and regions with a turnover of $164 million in 2006.
Two ways to cut your denim costs
Are increasing denim garment costs squeezing your bottom line? We at Zhejiang ZEC Group Garments Dept. can help.
Our in-house washing and long-term supplier relationships
With two washing factories, we are equipped to handle this costly process in-house. And as raw material prices rise, our long-term suppliers keep us competitive. We have cooperated with the same five suppliers for at least six years, and they reward our loyalty with priority pricing.
Custom designs in as few as three days
You’ll benefit from these cost savings with every order of our denim jeans, skirts and other garments. Bring us your custom designs and we will create a sample in as few as three days. We offer 100 new styles every season to match your sourcing needs.
100,000-piece monthly capacity
Our monthly capacity is 100,000 pieces, and we deliver in 30 days. Benefit from better pricing — contact us today.

History in 1855 r

History In 1855 R. Peters of Britain documented the first use of biaxial rotation and heat. This rotational molding process was used to create metal artillery shells and other hollow vessels. The main purpose of using rotational molding was to create consistency in wall thickness and density. In 1905 in the United States F.A. Voelke used this method for the hollowing of wax objects. This led to G.S. Baker’s and G.W. Perks’s process of making hollow chocolate eggs in 1910. Rotational molding developed further and R.J. Powell used this process for molding plaster of Paris in the 1920. These early methods using different materials directed the advancements in the way rotational molding is used today with plastics. Plastics were introduced to the rotational molding process in the early 1950s. One of the first applications was to manufacture doll heads. The machinery was made of an E Blue box-oven machine, inspired by a General Motors rear axle, powered by an external electric motor and heated by floor-mounted gas burners. The mold was made out of electroformed nickel-copper, and the plastic was a liquid PVC plastisol. The cooling method consisted of placing the mold into cold water. This process of rotational molding led to the creation of other plastic toys. As demand and popularity of this process increased, it was used to create other products such as road cones, marine buoys, and car armrests. This popularity led to the development of larger machinery. A new system of heating was also created, going from the original direct gas jets to the current indirect high velocity air system. In Europe during the 1960s the Engel process was developed. This allowed the creation of large hollow containers to be created in low-density polyethylene. The cooling method consisted of turning off the burners and allowing the plastic to harden while still rocking in the mold. In 1976, the Association of Rotational Moulders (ARM) was started in Chicago as a worldwide trade association. The main objective of this association is to increase awareness of the rotational molding technology and process. In the 1980s, new plastics, (polycarbonate, polyester, nylon, etc) were introduced to rotational molding. This has led to new uses for this process, such as the creation of fuel tanks and industrial moldings. The research that has been done since the 1980s at Queen University has led to the development of more precise monitoring and control of the cooling processes based on their development of the otolog system. Equipment and tooling Rotational molding machines are made in a wide range of sizes. They normally consist of molds, an oven, a cooling chamber, and mold spindles. The spindles are mounted on a rotating axis, which provides a uniform coating of the plastic inside each mold. Molds (or tooling) are either fabricated from welded sheet steel or cast. The fabrication method is often driven by part size and complexity; most intricate parts are likely made out of cast tooling. Molds are typically manufactured from stainless steel or aluminum. Aluminum molds are usually much thicker than an equivalent steel mold, as it is a softer metal. This thickness does not affect cycle times significantly since aluminum’s thermal conductivity is many times greater than steel. Due to the need to develop a model prior to casting, cast molds tend to have additional costs associated with the manufacturing of the tooling, whereas fabricated steel or aluminum molds, particularly when used for less complex parts, are less expensive. However, some molds contain both aluminum and steel. This allows for variable thicknesses in the walls of the product. While this process is not as precise as injection molding, it does provide the designer with more options. The aluminum addition to the steel provides more heat capacity, causing the melt-flow to stay in a fluid state for a longer period. Standard setup and equipment for rotational molding Normally all rotation molding systems have a number of parts including molds, oven, cooling chamber and mold spindles. The molds are used to create the part, and are typically made of aluminum. The quality and finish of the product is directly related to the quality of the mold being used. The oven is used to heat the part while also rotating the part to form the part desired. The cooling chamber is where the part is placed until it cools, and the spindles are mounted to rotate and provide a uniform coat of plastic inside each mold. Rotational molding machines Rock and roll machine This is a specialized single arm machine. It rotates or rolls the mold 360 degrees in one direction and at the same time tips and rocks the mold 45 degrees above or below horizontal in the other direction. Newer machines use forced hot air to heat the mold. These machines are best for large parts that have long length-to-width ratio. Because of the smaller heating chambers, there is a saving in heating costs. Clamshell machine This is a single arm rotational molding machine. The arm is usually supported by other arms on both ends. The clamshell machine heats and cools the mold in the same chamber. It takes up less space than equivalent shuttle and swing arm rotational molders. It is low in cost compared to the size of products made. It is available in smaller scales for schools interested in prototyping and for high quality models. More than one mold can be attached to the single arm. Vertical or up & over rotational machine The loading and unloading area is at the front of the machine between the heating and cooling areas. These machines vary in size between small to medium compared to other rotational machines. Vertical rotational molding machines are energy efficient due to their compact heating and cooling chambers. These machines have the same ability of the horizontal carousel multi-arm machines but take up a much smaller space. Shuttle or swing arm machine This is a single arm turret machine that moves the mold back and forth between the heating and cooling chambers. This machine moves the mold in a linear direction in and out of heating and cooling chambers. It is low in cost for the size of product produced. It is also available in smaller scale for schools and prototyping. Carousel machine This is one of the most common machines in the industry. It can have up to 6 arms and comes in a wide range of sizes. The machine comes in two different models, fixed and independent. A fixed carousel consists of 3 fixed arms that must move together. One arm will be in the heating chamber while the other is in the cooling chamber and the other in the loading/reloading area. The fixed carousel works well when working with the same mold. The independent carousel machines are available with more arms that can move separately from the others. This allows for different size molds, with different heating and thickness needs. Production process The rotational molding process is a high-temperature, low-pressure plastic-forming process that uses heat and biaxial rotation (i.e., rotation on two axes) to produce hollow, one-piece parts. Critics of the process point to its long cycle timesnly one or two cycles an hour can typically occur, as opposed to other processes such as injection molding, where parts can be made in a few seconds. The process does have distinct advantages. Manufacturing large, hollow parts such as oil tanks is much easier by rotational molding than any other method. Rotational molds are significantly cheaper than other types of mold. Very little material is wasted using this process, and excess material can often be re-used, making it a very economically and environmentally viable manufacturing process. Rotational Molding Process The rotational molding process consists of four distinct phases: Loading a measured quantity of polymer (usually in powder form) into the mold. Heating the mold in an oven while it rotates, until all the polymer has melted and adhered to the mold wall. The hollow part should be rotated through two or more axes, rotating at different speeds, in order to avoid the accumulation of polymer powder. The length of time the mold spends in the oven is critical: too long and the polymer will degrade, reducing impact strength. If the mold spends too little time in the oven, the polymer melt may be incomplete. The polymer grains will not have time to fully melt and coalesce on the mold wall, resulting in large bubbles in the polymer. This has an adverse effect on the mechanical properties of the finished product. Cooling the mold, usually by fan. This stage of the cycle can be quite lengthy. The polymer must be cooled so that it solidifies and can be handled safely by the operator. This typically takes tens of minutes. The part will shrink on cooling, coming away from the mold, and facilitating easy removal of the part. The cooling rate must be kept within a certain range. Very rapid cooling (for example, water spray) would result in cooling and shrinking at an uncontrolled rate, producing a warped part. Removal of the part. Recent improvements Until recently, the process was largely empirical, relying on both trial and error and the experience of the operator to judge when the part should be removed from the oven, and when it was cool enough to be removed from the mold. Technology has improved in recent years, allowing the air temperature in the mold to be monitored, removing much of the guesswork from the process. Much of the current research is into reducing the cycle time, as well as improving part quality. The most promising area is in mold pressurization. It is well known that applying a small amount of pressure internally to the mold at the correct point in the heating phase accelerates coalescence of the polymer particles during the melting, producing a part with fewer bubbles in less time than at atmospheric pressure. This pressure delays the separation of the part from the mold wall due to shrinkage during the cooling phase, aiding cooling of the part. The main drawback to this is the danger to the operator of explosion of a pressurized part. This has prevented adoption of mold pressurization on a large scale by rotomolding manufacturers. Mold release agents A good mold release agent (MRA) will allow the material to be removed quickly and effectively. Mold releases can reduce cycle times, defects, and browning of finished product. There are a number of mold release types available; they can be categorized as follows: Sacrificial coatings: the coating of MRA has to be applied each time because most of the MRA comes off on the molded part when it releases from the tool. Silicones are typical MRA compounds in this category. Semi-permanent coatings: the coating, if applied correctly, will last for a number of releases before requiring to be re-applied or touched up. This type of coating is most prevalent in today’s rotational molding industry. The active chemistry involved in these coatings is typically a polysiloxane. Permanent coatings: most usually, some form of PTFE (“Teflon”) coating, which is applied to the mold by a specialist vendor. Permanent coatings avoid the need for operator application, but may become damaged by misuse. Edon roto moulded rowing boat Materials More than 80% of all the material used is from the polyethylene family: cross-linked polyethylene (PE), linear low density polyethylene (LLDPE), and high density polyethylene (HDPE). Other compounds are PVC plastisols, nylons, and polypropylene. Order of materials most commonly used by industry : Polyethylene Polypropylene Polyvinyl chloride Nylon Polycarbonate These materials are also occasionally used (not in order of most used):: Aluminum Acrylonitrile butadiene styrene (ABS) Acetal Acrylic Epoxy Fluorocarbons Ionomer Polybutylene Polyester Polystyrene Polyurethane Silicone Various foods (especially chocolate) Natural materials Recently it has become possible to use natural materials in the molding process. Through the use of real sands and stone chip, sandstone composite can be created which is 80% natural non-processed material. Rotational molding of plaster is used to produce hollow statuettes. Chocolate is rotationally molded to form hollow treats. Products Rotational Molded Flamingo Designers can select the best material for their application, including materials that meet U.S. Food and Drug Administration (FDA) requirements. Additives for weather resistance, flame retardation, or static elimination can be incorporated. Inserts, threads, handles, minor undercuts, flat surfaces without draft angles, or fine surface detail can be part of the design. Designs can also be multi-wall, either hollow or foam filled. Products that can be manufactured using rotational molding include storage tanks, bins and refuse containers, doll parts, road cones, footballs, helmets, rowing boats and kayak hulls. Playground slides and roofs are also generally rotomolded. Design considerations Product design There are many considerations for a designer when designing a part. Which factors are most important to a client? For instance, a part may need to be cheap and a certain color. However, if another color is cheaper, would the client be willing to change colors? Designers are responsible for considering all the limitations and benefits of using certain plastics. This may result in a new process being decided upon. Designing for rotational molding Another consideration is in the draft angles. These are required to remove the piece from the mold. On the outside walls, a draft angle of 1 may work (assuming no rough surface or holes). On inside walls, such as the inside of a boat hull, a draft angle of 5 may be required. This is due to shrinkage and possible part warping. Another consideration is of structural support ribs. While solid ribs may be desirable and achievable in injection molding and other processes, a hollow rib is the best solution in rotational molding. A solid rib may be achieved through inserting a finished piece in the mold but this adds cost. Rotational molding excels at producing hollow parts. However, care must be taken when this is done. When the depth of the recess is greater than the width there may be problems with even heating and cooling. Additionally, enough room must be left between the parallel walls to allow for the melt-flow to properly move throughout the mold. Otherwise webbing may occur. A desirable parallel wall scenario would have a gap at least three times the nominal wall thickness, with five times the nominal wall thickness being optimal. Sharp corners for parallel walls must also be considered. With angles of less than 45 bridging, webbing, and voids may occur. Material limitations and considerations Another consideration is the melt-flow of materials. Certain materials, such as nylon, will require larger radii than other materials. Additionally, the stiffness of the set material may be a factor. More structural and strengthening measures may be required when a flimsy material is used. Wall thickness One benefit of rotational molding is the ability to experiment, particularly with wall thicknesses. Cost is entirely dependent on wall thickness, with thicker walls being costlier and more time consuming to produce. While the wall thickness can be nearly any thickness, designers must remember that the thicker the wall, the more material and time will be required, increasing costs. In some cases, the plastics may significantly degrade due to extended periods at high temperature. Also, different materials have different thermal conductivity, meaning they require different times in the heating chamber and cooling chamber. Ideally, the part will be tested to use the minimum thickness required for the application. This minimum will then be established as a nominal thickness. For the designer, while variable thicknesses are possible, a process called stop rotation is required. This process is limited in that only one side of the mold may be thicker than the others. After the mold is rotated and all the surfaces are sufficiently coated with the melt-flow, the rotation stops and the melt-flow is allowed to pool at the bottom of the mold cavity. Wall thickness is important for corner radii as well. Large outside radii are preferable to small radii. Large inside radii are also preferable to small inside radii. This allows for a more even flow of material and a more even wall thickness. However, it is to be noted that an outside corner is generally stronger than a inside corner. Process: advantages, limitations, and material requirements Advantages Rotational molding offers design advantages over other molding processes. With proper design, parts assembled from several pieces can be molded as one part, eliminating high fabrication costs. The process also has inherent design strengths, such as consistent wall thickness and strong outside corners that are virtually stress free. For additional strength, reinforcing ribs can be designed into the part. Along with being designed into the part, they can be added to the mold. The ability to add prefinished pieces to the mold alone is a large advantage. Metal threads, internal pipes and structures, and even different colored plastics can all be added to the mold prior to the addition of plastic pellets. However, care must be taken to ensure that minimal shrinkage while cooling will not damage the part. This shrinking allows for mild undercuts and negates the need for ejection mechanisms (in most pieces). Another advantage lies in the molds themselves. Since they require less tooling, they can be manufactured and put into production much quicker than other molding processes. This is especially true for complex parts, which may require large amounts of tooling for other molding processes. Rotational molding is also the desired process for short runs and rush deliveries. The molds can be swapped quickly or different colors can be used without purging the mold. With other processes, purging may be required to swap colors. Due to the uniform thicknesses achieved, large stretched sections are nonexistent, which makes large thin panels possible (although warping may occur). Also, there is little flow of plastic (stretching) but rather a placing of the material within the part. These thin walls also limit cost and production time. Another cost limiting factor is the amount of material wasted in production. There are no sprues or runners (as in injection molding), no off-cuts (thermoforming), or pinch off scrap (blow molding). What material is wasted, through scrap or failed part testing, can usually be recycled. Limitations Rotationally molded parts have to follow some restrictions that are different from other plastic processes. As it is a low pressure process, sometimes designers face hard to reach areas in the mold. Good quality powder may help overcome some situations, but usually the designers have to keep in mind that it is not possible to make some sharp threads used in injection molded goods. Some products based on polyethylene can be put in the mold before filling it with the main material. This can help to avoid holes that otherwise would appear in some areas. This could be also achieved using molds with movable sections. Another limitation lies in the molds themselves. Unlike other processes where only the product needs to be cooled before being removed, with rotational molding the entire mold must be cooled. While water cooling processes are possible, there is still a significant down time of the mold. Additionally, this increases both financial and environmental costs. Some plastics will degrade with the long heating cycles or in the process of turning them into a powder to be melted. Material requirements Roto-moulded traffic cones with reflective sleeve for night visibility. Due to the nature of the process, materials selection must take into account the following: Due to high temperatures within the mold the plastic must have a high resistance to permanent change in properties caused by heat (high thermal stability). The melted plastic will come into contact with the oxygen inside the moldhis can potentially lead to oxidation of the melted plastic and deterioration of the material’s properties. Therefore, the chosen plastic must have a sufficient amount of antioxidant molecules to prevent such degradation in its liquid state. Because there is no pressure to push the plastic into the mold, the chosen plastic must be able to flow easily through the cavities of the mold. The parts design must also take into account the flow characteristics of the particular plastic chosen. References ^ Beall 1998, p. 6. ^ a b c Ward, Noel M. (Winter 1997). “A History of Rotational Moulding”. Platiquarian Reprints. Archived from the original on 2009-12-03. http://www.webcitation.org/5lkadq2tF. Retrieved 2009-12-03.  ^ Todd, Allen & Alting 1994, p. 265266. ^ Beall 1998, p. 154. ^ a b Beall, Glenn (1998). Rotational Molding. Hanser Gardner Publications. pp. 152. ISBN 9781569902608.  ^ a b Beall 1998, p. 155. ^ a b Beall 1998, p. 18. ^ Beall 1998, pp. 6268. ^ http://machinedesign.com/article/putting-the-right-spin-on-rotational-molding-designs-0518 ^ Beall 1998, p. 69. ^ Beall 1998, pp. 7577. ^ Beall 1998, p. 71. ^ a b c Beall 1998, p. 70. Bibliography Beall, Glenn (1998), Rotational Molding, Hanser Gardner Publications, ISBN 9781569902608.  Todd, Robert H.; Allen, Dell K.; Alting, Leo (1994), Manufacturing Processes Reference Guide, Industrial Press Inc., ISBN 0-8311-3049-0, http://books.google.com/books?id=6x1smAf_PAcC.  Further reading Crawford, R, Throne, James L., Rotational Moulding of Plastics, William Andrew Inc. (2002). ISBN 1884207855 Crawford, R, Kearns, M, Practical Guide to Rotational Moulding, Rapra Technology Ltd. (2003). ISBN 1859573878 External links Association of Rotational Moulders Australasia British Plastics Federation – Rotational Moulding Overview Animation of the rotational molding process Categories: Casting (manufacturing) | Plastics industry

Реклама
Recent Posts