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Closed die forging is also named as impression die forging.In impression-die work metal is placed between upper and lower dies that attached to the anvil.Usually the hammer die is shaped as well.The hammer is then dropped on the workpiece so that the metal flows and fills the die cavities.The hammer is generally working on the workpiece at the speed of milliseconds.Depending on the size and complexity of the part the hammer may be dropped several times in quick succession.Excess metal is squeezed out of the die cavities,we call this flash.The flash cools more rapidly than the rest of the material;this cool metal is stronger than the metal in the die so it helps prevent more flash from forming.This also forces the metal to completely fill the die cavity.After forging,the flash is removed by punching machine(Of course,trimming die will also first made together with forging dies).

Background:Introduced to Fly Drop Forge during a trade show nearly 3 years ago,a U.S.-based manufacturer was seeking a closed die forging manufacturer to bridge the gap between their domestic operations and a client's goals of overseas saving.

Challenges:Aside from showing a cost savings,quality was the biggest challenge on this project.The closed die forging being requested had not been manufactured successfully overseas on a consistent basis by many factories.Fly company had to not only learn the product,but also creat the closed die forging processes through which super-clean parts that were adherent to tolerances could be produced.
The techniques of closed die forging are capable of achieving some of the strongest metal products when compared to other manufacturing processes.During the process of closed die forging,forging operations used can seal any cracks or empty spaces of the billet,therefore creating very strong metal parts.The typical method that can achieve this is known as closed die drop forging,which is when a plate of metal is placed between two dies,and then compressed under extreme pressure within the closed cavities to form the shape between the molds.The cavities restrict the flow of the metal inside the die (mold),and the metal will flow to fill the space within the cavity,resulting in the shape and dimensions of the mold design.Depending on the type of metal used,this process can be done while the metal is hot forging.

The Closed Die Forging process forces the material to flow and fill the space in the mold also changes the grain structure of the metal while making the product very strong.The flow is controlled in the direction what will achieve the strongest results and best grain structure.The high pressures of the process condenses the individual grains of the metal,resulting in higher density of the material and stronger properties.
It is a custom process for manufacturing drop forgings,so there exsits difficulty to develop a new product.We all know that there are different requirements for different products,some just require drop forging only,some require machining to reach tighter tolerances and some require heat treatment......So it is really unknown that if the potential suppliers we choose are suitable.If buyers would like to custom cheap drop forgings from China with good quality,it is really necessary for them to arrange a visit before ordering.

So when visiting,what should purchasers pay attention to?

*What is the scale of the company?
The scales of a forging company will decide its capability.A scaled drop forging company should have more than 80 staff.Like our company,there are about 150 staff,which is the largest drop forging company in Ningbo.It does not mean small scale drop forging company can not supply high quality products,at least its production ability is limited,and we can not say the lead time is ensured.
Together with investment casting,closed die forging is also one of the main metal forming processes for precision parts.Comparing with closed die forging companies in other countries(USA,UK,Canada),it will be much cheaper to custom closed die forgings in China for its low material cost,low larour cost,ect.So after China took part in WTO in new century,more and more people import closed die forgings from China on a regular basis.

Then how to import closed die forgings from China?
First of all,importers should have a basis understanding on Chinese closed die forging market.Ningbo is the main production base for closed die forging parts.We can see lots of closed die forging factories with different scales in Ningbo.Take our company as example,Fly Drop Forge is the largest closed die forging factory in Ningbo with 150 workers.Each year,we deliver about 10000t products to countries around the world.By virtue of its good geographical advantage(Ningbo seaport),we can arrange delivery in the shortest time.
Closed die forging cost is the cost that buyers who would like to choose closed die forging as their metal forming process for its superior advantages.Closed die forging process will make products in high strength and good properties.And there will require less or no machining with no defects and good surface finish.Our PO PROCEDURE will guide you how to buy closed die forgings from our company.Below are the main factors that will greatly affect the cost of a closed die forging product:
  • Tooling/die cost--As the forging is "closed die",not"open die",so a set of upper and lower dies will be designed and produced first before start forging process.To achieve high precision products,such dies must be machined from tool steel block with cnc machines.Normally it will cost about 7-10 working days to finish closed die forging dies.And the tooling/die cost will depond on the product structure and dimensions,normally at 2000usd-4000usd.
Steering knuckle is one of the main parts of automotive steering bridge, to be able to make the car driving stable and sensitive relay driving direction.One Role is to pass on steering wheel turning Angle value to the car front wheel effectively,timely control the car moving route,thus to ensure the safety of the car;Another effect is to bear load of 
the front car,supporting and driving wheels turn around the king pin,in the condition of the car moving,undertake variable impact load.So steering knuckle requires not only reliable strength,and must ensure its high machining accuracy.Its geometry is complicated,so the machining sections are more,the machining precision of high and low will affect the vehicle running accuracy.Based on the forging analysis of two different forging process of steering knuckle,discussing the influence of parting ways,distribution of allowance on machining processing.

Steering knuckle is the safety component of a car.It may cause heavy traffic accidents if there is any quality problem.The geometry of automobile steering knuckle is complex,belongs to compound type of forgings,consists of the fork,plate,bar of three parts.So the forging technology need to aspire to forming characteristics of three kinds of forgings.Steering knuckle is regards as the most complex forging parts in forging industry.


Now there are some car steering knuckle also increased the steering arm and tie rod arm,whose structure is more complex,the current steering knuckle is widely used in the van and light vehicle,also have individual heavy vehicles use this structure of steering knuckle.As shown is a light vehicle steering knuckle,its structure is very special,and its forging is difficult.Steering knuckle forging in the part was made by use of 3t,5t,10t die forging hammer,13 tm double-action hammer and some other forging equipments,but the production efficiency is low and product quality is poor.In recent years,auto production every year increases by double-digit growth,and the demand of steering knuckle is increasing rapidly,the old mode of production has not suitable for the needs of the modernization and mass production.
There are a lots of metal forming process for a metal designed part,such as casting,forging,stamping,welding fabrication,ect.Each process has its own characteristics.Sometimes we can use casting or forging either.But by comparison,purchasers will prefer steel forging as the metal forming process.Below we explain in detail why use steel forging as your metal forming process?What are the advantages?

Consistency
The consistency of steel material from one forging to the next,and between separate quantities of forgings is extremely high.Steel forged parts are made through a controlled sequence of production steps rather than random flow of material into the desired shape.Uniformity of composition and structure piece-to-piece,lot-to-lot,assure reproducible response to heat treatment,minimum variation in machinability,and consistent property levels of finished parts. 
hot die forgingHot die forging press is a special forging equipment of batch production and mass production of black and non-ferrous metals that are used for closed die forging.It is widely used in automotive industry,agricultural machinery,bearings,valves,engineering machinery,hardware tools,oil industry and the forging of the defense industry production.Can complete closed die forging forming of metal parts like blade,horns,gears,chain plate,valves,wrench,bulldozer,connecting rod,ect.

There are mainly three series of hot die forging presses,namely NSP,NMP and NKP.Of course,there are also some auxiliary forging equipments,such as roll forging machine,trimming machine,heating machine,ect.

Characteristics of hot die forging press 

Hot die forging presses have advantages of high efficiency,simple operation,convenient maintenance,and suitable for automation forging assembly line.High blow speed,mould thermal contact time is short,and forging dies service life is long.Using upper and lower design will make draft angle decreasing and forging material saving.High resistance to tilt rate, lead to high precision guide rail and high quality steel forgings.PLC control,multiple safety operating circuit system,can ensure the operator safety.Left and right sides of the body is equipped with the work window,so that forgings delivery is convenient.Special card die liberation device,make release of dies rapidly,and the operation is simple.Reliable centralized lubrication system and manually add lubrication system,can effectively reduce the friction loss.Equipped with advanced international tonnage meter,can visual display forging force,and set the overload alarm.
Case:We are a UK based precision machining company for metal components with tight size tolerances for all industries,especially for automotive,construction,forestry,ect.We are now looking for a drop forging company to supply connecting rod blanks only,and we will do machining here locally.

Analysis:This customer contacted us via email and sent us the drawings both in pdf and 3d format.Our sales manager forwarded the drawings to our engineer and marked main information(material,quantity,weight).From the product information we can judge that it is within our production ability.But there is an hardness requirment(45-50HRC),which can only meet by heat treatment.So we are confused if we heat treat forged connecting rod,will it be machinable by our customer?We did talk about this issue with them,and the result is that heat treatment will be done in UK locally after machining.

forged connecting rod
Over the past 50 years,auto parts manufacturing technology is in the continuous improvement.Today,what takes a leading role in the market is the low cost,high strength anf tight 
tolerance.In drop forging production process,the strict requirements for forgings are just as important as to the requirements of the finished product.Drop forging companies 
around the word constantly look for a better production method to achieve the objectives and requirements of the auto parts buyers.

Forged connecting rods are regarded as the quality standards of internal combustion engine to use for decades.Over the years,production methods of connecting rods are constantly changed,includingforging hammer forging,press forging,metal powder forging and casting.In the early years of auto industry development,forging hammer forging is considered to be one of the best forging method.However,in the middle of the twentieth century,due to the higher requirements for quality and tolerance,the forging method must be changed,so manufacturers began to use mechanical press to replace forging hammer.The most effective way to reduce the manufacturing cost is to improve the material utilization.Increasingly stringent requirements for weight and size tolerance promotes the use of powder forging method.Another advantage in addtion to tolerance is that we could forge connecting rod cover toegther with connecting rod,and can open the cover from connecting rod,thus manufacturing cost can be saved.In the late twentieth century, forging method developed into "open" forged steel connecting rods(Why use steel for drop forged connecting rods in automotive cylinder engine?),it is also one of the strengths of the powder forging.The strength of forged steel connecting rod is higher than powder metallurgy rod.Increase as the engine compression ratio,compared with the powder forging connecting rod(wrought vs powder forged connecting rods),high strength of forged steel connecting rod becomes more satisfactory,this forging method can meet the both strict requirements of weight and size tolerance.