Injection Mold WIKI

When it comes time to decide whether to use graphite or copper electrodes in your shop, it’s important to look at the big picture. According to Stu Haley, regional manager of Madison Heights, MI-based Belmont Technologies, Inc., a provider of EDM supplies, tooling, accessories and machines, “To say which electrode works best is very difficult, it is totally applications-driven. So much depends on what you have to work with on your shop floor in the way of support equipment. Both copper and graphite provide approximately the same end result. The difference is time to EDM the work and electrode manufacturing time and cost.”

Haley explains that choosing an electrode material is often a result of where you were born and what type of EDM equipment you use. “For example, graphite was basically developed in the United States back in the early 1960s, so the American EDM equipment manufacturers in those days concentrated on the graphite circuitry when designing their equipment,” he says. “Whereas, since the European and Asian EDM equipment manufacturers didn’t have access to graphite, they developed copper circuitry.

“If you have newer equipment built after 1990, the electrode material of choice in North America is graphite,” he adds. “This is used in 90 percent of the applications. In Europe and Asia, graphite is becoming more popular as an electrode material because of availability, machinability, and speed of cutting.” Following are some of the advantages and disadvantages of each material so that you can decide which is best for your application.

 

Graphite

Advantages and Benefits

Sold by grades, graphite cuts approximately three times faster than copper, according to Haley. “What makes a good grade or a poor grade is particle size,” he explains. “Particle size gives you strength, machinability and greatly influences the metal removal rate, wear, and the surface finish. Graphite is made up of carbon particles that are put through a graphitizing process to produce graphite. The smaller the particle size is, the better the graphite. Particle sizes in different grades of graphite can be .0006″ for general-purpose use to .00004” for the extremely fine detail and superior surface finishes. Graphite can be purchased in big blocks, and then cut up to be machined, or it can be ordered precut or ground into the size you require.

“Graphite machines very easily – you can mill it, grind it, turn it, drill it, tap it, even file it to whatever shape you want,” Haley continues. “Another advantage of graphite is that it doesn’t burr. You can put it on a duplicating machine or a graphite high-speed mill and cut out complex shapes and forms, and once it’s cut you are finished – with no deburring.”

 

 

Limitations

If mold maker has the older fabricating equipment, machining graphite electrodes will result in dust particles on the shop floor and in the nearby machines. However, the new high-speed mills that are sold today are specially designed to machine graphite. “They are totally enclosed and have a vacuum system to remove all of the dust,” Haley points out, “and there are some machines that can even cut square internal corners.”

 

Copper

 

Advantages and Benefits

Haley notes that copper can be cut on wire EDM machines, but there are only certain graphites that can be cut on a wire machine – the particle size should be five microns or less. Copper also is a little more forgiving in a poor flush situation than graphite. “In EDM, if the flush doesn’t remove the eroded particles or chips out of the cutting area, there’s something that can occur where you get a non-pulsating, direct flow of current from the electrode to the workpiece,” Haley explains. “The result of this is a pit in the workpiece. Copper is more forgiving in those applications – all metallic electrodes are – they won’t arc out as fast.  But some of the newer EDM power supplies have adaptive logic or fuzzy logic, which eliminates the problem altogether. Copper – when used in specific settings with the correct flushing techniques using a CNC machine or a machine with an orbiting system – can produce a mirror-like surface finish. This is useful in small cavities where it is difficult to polish.”

 

 

Limitations

“Copper is more difficult to machine,” says Haley, “and when you mill it, it has the tendency to stick to the cutter. When you grind it, it can clog up the grinding wheel – it heats up quickly and has a tendency to grab the grinding wheel. You’ll have burrs no matter how you machine it, so you have to deburr it. Size and weight also can be an issue. A 12″ x 7″ x 2 3/4” piece of copper weighs 75 pounds, whereas a piece of graphite the same size is 11 pounds.

“The bottom line uses what you think will work best in your shop with the equipment that you have available,” Haley continues. “If some electrodes are beyond your machining ability, have someone make them for you. You have to base it on your own experience and the resources you have available. Ask for suggestions from the equipment manufacturer or from your electrode material supplier. Regardless of what electrode material or combination of materials you decide on, be sure that you know the speeds and feeds to machine the material safely. When in doubt, ask.”

 

Article Resource: https://www.moldmakingtechnology.com/articles/using-copper-and-graphite-electrodes-look-at-the-big-picture

Before we spent lots of money to make molds, some new project investor will make rapid prototyping to check the mechanical function or verify the designing,rapid prototype can be made of plastic,steel or aluminium.at the monment we have many methods to make prototypes, such as CNC machining, SLA technology and Vaccum custing technology.

 

Rapid Prototyping (RP) is a quick and economical way to make the sample according to your drawing or your idea, you can do assembly to verify the mechanical function, we can make painting,silk print and runner coationg,as the technology develop,the finish of prototypes reach the same level of mass production product.then you can see the real aprearance of your designning,sometimes customers use rapid prototype for business exhibition as real product.Good quality prototype is one of the reason,another important is the economic cost and short lead time,rapid prototype normally take one week,but molds will take one month at least,cost is also different,prototype will cost less than 300USD,but molds cost more than 2000 USD even if you find the cheapest mold manufacturer in China.

Also the rapid protyping have another important function:find the mistake or imperfection in the designing at the beginning of R&D and help designer optimise the designing step by step,if you find the problem after you build the mold,it will take thousands of USD to modify the tooling.

 

 

CNC Machining prototyping
This is most popular way to make rapid protypes in China.first ,the CNC machines is not expensive as others,it is less risk to invest the equipment.Second,they can make large size prototypes
Max size up 1100mm x 650mm x 470mm,
Advantages: Large size, high strength, good toughness, short delivery time.

 

SLA technology
tereolithography (SLA or SL; also known as optical fabrication, photo-solidification, solid free-form fabrication, solid imaging and Resin printing) is an additive manufacturing or 3D printing technology used for producing models or prototype
Application: toy, electric case parts with complex surface
Advantages: complex structure capable, high strength

Vacuum-custing technology
Produce a silicone mold with a prototype part under vacuum, use the silicone mold to clone parts.
Advantages: Low cost, fast, it is very cheap to duplicate the prototypes,it have big advantage if you want 10-50 pcs parts.

As we kown, the auto business develop very quickly in past ten year,more and more newest go to the market, lots of automovtive components are made from plastic,that means it need large amount of molds made.

Eco molding Co., Ltd is specialized in various types of auto bumpers moulds and it’s auxiliary parts such as grilles. Eco MOULD produce  bumper molds for international automotive OEM brands and doing well in bumper molding. One of the particular features of Eco molding is short development time ,it will help our customer launch the product in the market.
we are the company special in automotive parts molding.

As a new material for auto parts, plastic parts can reduce the weight of cars and is energy saving, thus are widely used in auto industry. Plastic material gives auto manufacturer more flexibility in car design, i.e.: inner decoration spare parts, panels, door trims, ABS breaking system, bumpers, triangle, spoiler, etc. Our company has certified by ISO9001, along with professional design team, high performance equipment, we have been cooperative partner of many car manufacturers both china and overseas. our company are capable of providing integral design, structural design, auto mold development, product injection, including panel, door trims, air condition, and bumper analysis for Automotive Parts Molding.

Product design and mold flow analysis
In the process of product design, mold flow analysis software is used to work out best point of the flow. At the same time, to minimize cooling effect, cycle time, warping problems of the product, thus avoiding deformation, welding mark, shrinkage problem. Every important assembling part will be check by jigs and gauges to make sure that all products fit well in its set.

Auto mold processing technology
Measuring is of high importance in automotive plastic mould, which affects the assembling and fitting effects of all auto parts. The five-axis nc machine can speed up the feed process, shorten manufacturing cycle, optimize tooling system and simplifying processing cycle time and guarantees the precision of the auto mold.

Auto parts injection technology
In the process of injection, material property, clamping tonnage, injection pressure and cooling system should be taken into serious consideration. Auxiliary equipment as water chiller, mold temperature controller machine should be used when necessary, thus to shorten the cooling time and to improve productivity. Spare parts should be put carefully into specially appliance in order to preserve it well.
Auto parts Mould specific processing:
1.As per sample or 3D drawing design the mould.
2.Purchasing the steel.
3.CNC machining,Drill,Heat treatment
4.High speed CNC machine
5.Assembling and fitting
6.Mirror polish
7.The first mould test
8.Delivery

PVC pipe fittings Mould ( for high pressure and low pressure，for water supplying and water discharging) ，PVC is sometimes known as ‘Vinyl’ in Europe and predominantly so in North America. In Europe, ‘Vinyl’ usually refers to certain specific flexible applications, such as flooring, decorative sheets and artificial leather，This chlorine gives to PVC excellent fire resistance。

 

Nowadays people start to use PVC for pipe fitting,because they are much cheaper and durable compared to metal ones,our field cover as follow:
1. CPVC pipe fitting for high pressure.
2. UPVC pipe fitting for water drainage
3. PVC belling pipe fitting mould( with collapsible cores for pressure water supply).
4. Electricity cable pipe fitting, built in-wall various PVC pipe fittings.

The technical solutions for PVC pipe fitting moulding and PVC pipe fitting mould manufacturing. PVC is a kind of special material which need special injection molding process.
The basic feature of PVC material:
1. Hard PVC material low MFI
2. PVC with high corrosive
3. PVC with low temperature melting
4. Easy decomposition

As professional PVC pipe fittings company,we have advantage as following:
1.Good steel with high hardness
2.Good accessories with high brightness
3.Good machining with high precise
4.In-time response on email, telephone calls
5.In-time supply the quotation and mould designs
6.In-time commnication on the technical points
7.In-time sending pictures for the mould machining progress and mould finishing schedule
8.In-time mould test and sample delivery
9.In-time mould delivery

Injection molding is the most commonly used manufacturing process for the fabrication of plastic pieces. A wide variety of products are manufactured using injection molding, which varies greatly in their size, complexity, and application. The injection molding process requires the use of an injection molding machine, raw plastic material, and a mold. The plastic is melted in the injection molding machine and then injected into the mold, where it cools and solidifies into the final part. The steps in this process are described in greater detail in the next section.

Plastic parts are used in a variety of products including home appliances, consumer electronics, power tools, and as automotive dashboards. Other common thin-walled products include different types of open containers, such as buckets. Injection molding is also used to produce several everyday items such as toothbrushes or small plastic toys. Many medical devices, including valves and syringes, are manufactured using injection molding as well.

the plastic parts have many advantages compare to metal parts, glass, wood.such as lightweight, cheaper price, and the cycle of production will be shorter the different hardness and chemical stability. and better insulation performance.

As we know, if you want to produce a plastic product,you should make a injection mold tooling first.the mold is the key equipmemt for the shape.so let’s lear what the injection mold tooling is.

The injection molding process uses molds, typically made of steel or aluminum, as the custom tooling. The mold has many components, but can be split into two halves. Each half is attached inside the injection molding machine and the rear half is allowed to slide so that the mold can be opened and closed along the mold’s parting line. The two main components of the mold are the mold core and the mold cavity. When the mold is closed, the space between the mold core and the mold cavity forms the part cavity, that will be filled with molten plastic to create the desired part. Multiple-cavity molds are sometimes used, in which the two mold halves form several identical part cavities.

The mold core and mold cavity are each mounted to the mold base, which is then fixed to the platens inside the injection molding machine. The front half of the mold base includes a support plate, to which the mold cavity is attached, the sprue bushing, into which the material will flow from the nozzle, and a locating ring, in order to align the mold base with the nozzle. The rear half of the mold base includes the ejection system, to which the mold core is attached, and a support plate. When the clamping unit separates the mold halves, the ejector bar actuates the ejection system. The ejector bar pushes the ejector plate forward inside the ejector box, which in turn pushes the ejector pins into the molded part. The ejector pins push the solidified part out of the open mold cavity.
The mold life is different depends on the steel of inserts,if the inserts are made by pre-hard steel.the usual mold life is 300,000 shots.if the mold core and cavity inserts made by harden up steel,such as 1.2344,the mold life will reach 1,000,000 shots. The mold tooling is not cheaper because that the material(steel) is expensive,the process is very complicated and need rich experience staff.the price ranged from 1000-300,000USD

• Mold surface is free of pits, rust, extra unused rings, water fitting, gas, other defect which affect the appearance of the hole, etc.,
• More than 1.5mm chamfer on all mold plates.
• The cooling fitting should be upper than the mold surface,and is better to locate in unoperate side
• Every lift ring should be marked their size if their weigh over 10 kg,or make sure the friendly use.
• Make sure supporter is higher than blocks by 0.05-0.15mm.
• All cooling should be marked “IN” and “OUT”,adding sequence number if needed, such as IN1, OUT1, IN2, OUT2.
• Each plates should be marked with datum symbols and numbers ,position at 10mm away from the edge, writing should be clear, beautiful, neat, spacing evenly.
• Small molds must have lifting holes in A plate and B plate, all plates of large mold must have lifting holes.
• All four corners of the mold should have pry slot between two plates.

If you want to make plastic parts or develop some product and looking for some mold factory,there are six principles as below
Principle I: reliable team and good attitude
the injection mold factory should have rich experience engineer and team work., the team is equipped to fly. When you find injection mold factory, you can not allow manufacturers to ignore you, probably because too many orders start at the same time, probably because they didn’t pay attention to detail and so on, so to make a phone call in two days or three days a week, take a look. To maintain a relationship with them.
Principle II: The ability of descripe a good prospect
Tell him your project have a good future, rather than ask him to help you do that. Let him know that you give the best products to him, but also it is his chance. In fact, in the final analysis, it is to your supplier but also as one of your investors, so that they have an idea with you success. Share with your mold factory your understanding of the industry, From the boss to tool makers, should be enough respected.
Principle III: ID-MD, mold making and injection molding in one stop

Industrial design and structural design are done in one factory , although there may be some small problems, but the advantages in one factory should be bigger. Mold making and injection molding should be done the same

 

Principle IV: Not the best,but the proper
Not the biggest and best mold factory is suitable for you, nor is it a small mold factory is simply not considered. Select mold factory, depending on your project, precision,development cycle and costs. Precision and cycle always conflict with the cost. Here you have a balance. Also not a small mold factory, we can help you save money. Small mold factory will often respond quickly. But where there will be a lot of such irregularities proplem.
Principle V: The standard is the key
To avoid unnecessary fighting and possible miscommunications. You should record every design change,all drawing,spec and reports should be written in paper and signed

 

Principle VI: patent application or NDA
Normally you should sign a NDA or Patent application before you make molds,it will protect your product not to be coppied.