Die Casting Machine Buyers Guide

Transcription

1 Die Casting Machine Buyers Guide Cold Chamber Die Casting Machine for Aluminum Hot Chamber Die Casting Machine for Zinc How to Choose The Right Machine

2 FORWARD: This ebook is a continuing work in progress. It is designed for those people who know very little or nothing about die casting, yet are interested in either starting a die casting business or in the process itself. The descriptions contained in this ebook are introduced and explained in the most basic form and in layman's terms, so they can be understood even by those not familiar with die casting. As time permits, I will add more information and new headings. If you would like to add to this ebook from your own experience in the die casting industry, please feel free to contact me at [email protected] Enjoy, and all the best, Jack Iwanski Jack Iwanski Die Casting Machine Buyer s Guide Copyright 2016 Jack Iwanski

3 INTRODUCTION TO DIE CASTING: Die casting is a rewarding, exciting and profitable business. However, like all businesses it has its challenges and pitfalls. The key is to identify what they are and how to either overcome them or avoid them all together. Over my many years in the die casting business I have seen all sorts of approaches to the die casting business. However, I have seen time and again that buying good quality used equipment has been the secret sauce to the success of many die casters. Regardless, if it has been during good times or bad times, the companies who have kept their costs down and have taken advantage of the benefits of used equipment are still in business and are making a profit. The reason is simple. They have a competitive edge over those who have gone into deep debt buying extremely expensive, new machines. DIE CASTING EXPLAINED: In the die casting process a mold (called the die) is required. The die is constructed from very high quality steel specially made for dies. The dies are reusable and are made of two halves. During the process of die casting, molten metal is injected into the closed die under very high pressure through a relatively small hole in one half of the die. When the molten metal has solidified sufficiently, the two parts of the die are opened to expose the actual casting inside. The casting is then removed from the die, cooled further and then finally trimmed. The trimming separates the gates and runners from the casting. The gates and runners are incorporated into the die design as a way to distribute molten metal to the various parts of the die. The trimmed gates and runners are then usually re-melted with new metal also being added. After trimming, further operations can be performed such as drilling and tapping, powder coating and assembly of finished components, etc. APPLICATION: Die casting is used to make various cast alloy parts in different sizes for a wide variety of applications. The die casting process is very efficient and can produce large volumes of castings in a short period of time and has extremely precise repeatability. The flexibility of product types, casting sizes, a virtually infinite possibility of shapes makes die casting the preferred process for a wide variety of industries. While die casting dies are more expensive than dies for other forms of casting, such as sand casting and permanent mold casting or gravity casting, die cast parts offer many advantages such as very high tolerances, precise repeatability, less porosity, sharply defined parts and a possibility of textured or smooth surfaces. Die Casting Machine Buyer s Guide Copyright 2016 Jack Iwanski

4 The flowing chart is a comparison of die casting to other types of casting methods. Each goal is rated 1 to 3, with 3 being the best and most economical solution. As you can see from the chart, while the tooling cost is initial more, the Cost Per Part is the lowest of all casting methods. Casting Methods: GOAL Die Casting Permanent Mold Investment Casting Sand Casting Surface Finish Complex Shapes Size Accuracy Porosity Production Speed Tooling Cost Cost Per Part LIMITATIONS: With the development of CAD programs, die casting simulation programs and the development of sophisticated shot monitoring and shot control systems of die casting machines, most limitations for die casting have been overcome. There are basically only two limitations left. The first is size and weight of the casting. The size of the physical dimensions of the casting will determine the size of the machine that is required. However, obviously there is a size limit to this. The item being cast must fit into the mold (die) with sufficient clearance all around the casting and then mold (die) itself then must fit into the die casting machine. The mold (die) clearance determining factor is the "distance between tie bars" on the die casting machine. The mold (die) must be able to fit between these dimensions with reasonable clearance. So for example, a 600 ton die casting machine usually will have a distance between tie bars of 737 mm H x 737 mm W (29"H x 29"W). If the mold (die) is bigger than that you will have to move up to the next size of machine. The largest size of machine ever produced has been a 4000 ton machine with a "distance between tie bars" of 1780 mm H x 1780 mm W (70" H x 70" W) and a max shot weight of 65kg (143 lbs). The other limitation is the weight of the casting. For example, a 600 ton die casting machine usually has a maximum shot weight of about 7 kg (15 lbs). The shot weight is defined as the total weight of the metal that is injected. The shot weight therefore includes the actual casting plus any runners, gates and the brisket. The reason for the weight limitation is that the die casting machine must have Die Casting Machine Buyer s Guide Copyright 2016 Jack Iwanski

5 sufficient power and velocity to inject molten metal through the shot sleeve into the die and to fill the die cavity completely with the metal before the metal starts to solidify. The whole process must be done within milliseconds and at tremendous pressure otherwise the extreme ends of the mold (die) will not get filled or will be partially filled. The result will be a scrap castings and wasted effort. While the calculation of "weight to velocity to time" is extremely complicated, die casting machine manufactures have already done most of the work for you by "standardizing" this ratio. As such, each machine manufacturer builds a relatively standardize range of machines with relatively standardized shot weight ranges and relatively standardized distances between tie bars. HOW TO SELECT AND BUY A DIE CASTING MACHINE: There are many things to take under consideration when buying a die casting machine. This section has been designed to simplify the process of sifting through all the options and selecting the right machine for your needs. NEW OR SECONDHAND? This is the age old question that most people have. However, most people do not realize that when it comes to die casting machines (as with many other products), manufacturers of these machines produce several "export versions" depending on which "region" of the world they will be sold to. For example, die casting machines produced for the North American market will vary greatly in the quality of materials and technical capabilities when compared to machines produced for "developing" countries. The reality of the matter is that the North American market is much more "mature" and generally speaking has much greater requirements and expectations than other developing markets do. In addition, the level of sophistication, the product technology and budgets for equipment acquisition is greater as well. As such, many die casting machine manufacturers who have been relatively successful in producing machines for developing counties have had almost NO success in developed countries like North America, Europe and other developed markets. In the world market, these machines have become known as "disposable" machines (possibly the term came from disposable shavers). Where as a machine made in North America or Europe can be rebuilt many times over and over due to superior quality steel, such disposable machines have a very short lifespan of only a few years. After that, it is very hard, if not impossible, to rebuild them properly since the quality of the metal is very poor. Die Casting Machine Buyer s Guide Copyright 2016 Jack Iwanski

6 For a lack of a better example, the following is an illustration of a vehicle made for the "developing market" and a vehicle made for a "developed market". EXAMPLE: WHICH WOULD YOU PREFER TO DRIVE AND BE SEEN IN EVERY DAY?? OR New Domestic Brand Produced for "Developing Markets" Price: USD $ 20,000. Secondhand World Class Brand Produced for "Developed Markets" Price: USD $ 15,000. The answer to the above question becomes even more obvious when one takes into account the long term performance of the vehicle, the reliability, the comfort, the amount maintenance, the frequency of maintenance and finally the resale value. It is very similar with a die casting machine. The question takes on even more significance when you keep in mind that many of your customers for die casting projects will want to visit you and see your equipment. If you have good quality, Brand Name equipment it will be a lot easier to build confidence in your customer and get the project from them. This is even more so the case with larger orders and dealing with larger companies. Educated customers today know that if you have good quality, world class, brand name machines, then there is a much higher chance that castings will be good. It makes sense. At the end of the day, good customers (the kind that you want) need to be convinced that you can do the work and that the work will be done on good equipment. Simply put, seeing good equipment in you facility, helps them to sleep well at night. Die Casting Machine Buyer s Guide Copyright 2016 Jack Iwanski

7 HIGH PRESSURE DIE CASTING MACHINE TYPES: There are 3 basic types of high pressure die casting machines. 1) Cold Chamber: Used primarily for aluminum castings (occasionally specialized machines for brass and magnesium) 2) Hot Chamber: Used primarily for zinc and lead (occasionally specialized machines for brass and magnesium castings) 3) Multi-Slide: Used for zinc (occasionally specialized machines for magnesium castings) Die Casting Machine Buyer s Guide Copyright 2016 Jack Iwanski

8 DIE CASTING MACHINE CLASSIFICATIONS: There are 3 basic classifications of die casting machines. 1) FULLY AUTOMATIC: This term means that the die casting machine can perform the whole casting process (mentioned above) "automatically" without operator intervention or help in the form of manual labor. As such, in order for the machine to be called "fully automatic" the machine must include all three (3) automatic devices (referred to in the industry as automation); a) automatic mechanical ladler b) automatic mechanical sprayer c) automatic mechanical extractor. Die Casting Machine Buyer s Guide Copyright 2016 Jack Iwanski

9 2) SEMI AUTOMATIC: This term means that the die casting machine can perform only one, or at the most two, of the die casting processes (mentioned above) without manual labor by the operator. The rest of the process requires manual labor by the operator. In order for the machine to be called "semi automatic" it must include at least one (1) or at the most two (2) automatic devices; an automatic mechanical ladler, an automatic mechanical sprayer or an automatic mechanical extractor. Die Casting Machine Buyer s Guide Copyright 2016 Jack Iwanski

10 3) MANUAL: This term means that the die casting machine cannot perform any of the die casting processes (mentioned above) automatically. All three processes, ladling, spraying and extraction must be done by the operator. While a worker can do all the primary machine processes, to remain competitive it is recommended to consider a fully automatic machine. The only exception to this would be for a company which does very small runs or batches of castings. Even in such circumstances, more likely than not a semi-automatic should be considered. The savings in labor costs and consistency of casting quality is substantial. Not only that automation allows for more predictability and foresting of production output. Die Casting Machine Buyer s Guide Copyright 2016 Jack Iwanski

11 DIE CASTING MACHINE PROCESSES: There are 3 primary process involved with make a die casting. They are classified as follows; 1) Preparatory Processes (grey) Preparatory processes can include by are not limited to die installation, ingot preheating, ingot melting and holding, fluxing the melt and anything else needed in preparation for the main machine processes. The following illustrations show a melting/holding furnace as part of both Manual and Fully Automatic preparatory process. Die Casting Machine Buyer s Guide Copyright 2016 Jack Iwanski

12 2) Primary Machine Processes (yellow) Primary processes in die casting include only the immediate processes that are needed for the die casting machine to produce a casting. There are 3 primary machine processes; a) Ladling: The process of transferring the molten metal from the furnace to the shot sleeve. This process can be done manually by the machine operator or automatically but a mechanical ladling device. (NOTE: In hot chamber machines the process of transferring the molten metal is done internally in the machine. As such, no external mechanical device is need). b) Spraying: The process of spraying die release liquid or compound on one or both sides of the die before the next cycle starts. This process can be done manually by the machine operator or automatically but a mechanical spraying device. c) Extraction: The process of removing the finished casting from the die before the next cycle starts. This process can be done manually by the machine operator or automatically but a mechanical extracting device. The following illustration shows the full primary machine process. Die Casting Machine Buyer s Guide Copyright 2016 Jack Iwanski

13 3) Secondary Processes (orange) Secondary process in die casting can include initial inspection, quenching, trimming and transport away from the casting machine area using a conveyor. 4) Tertiary Processes There are many tertiary processes that casting can go through. Among them are surface finishing, drilling, tapping, painting, assembly, etc. Die Casting Machine Buyer s Guide Copyright 2016 Jack Iwanski

14 WHICH SIZE IS RIGHT FOR YOU?: Die casting machines are classified based on locking tonnage. For example, an 800 ton machine has a locking tonnage of 800 tons. Machine specifications vary from brand to brand and even sometimes from year to year. The following chart shows some basic average specifications gathered from several brands over a period of time. Of course, some manufacturers have produced sizes of machines which fall in between the sizes shown below (for example 500 ton) however, the chart is just for basic reference. Each machine size has a flexible shot range (low and high). The shot range can be switched by changing the diameter of the shot sleeve and plunger hence the shot weight below shows a range that is usually possible with each size of machine. A small amount of machines larger than 2500 ton have been manufactured, however these are very rare and extremely expensive. Since a die casting machine is selected based on a combination of die size and shot weight, the following tables show some basic guidelines in selecting the correct size of machine for your needs. The distance between tie bars is the maximum size of die that will fit into the machine. The die can be single cavity or multiple cavity. Average Specifications of COLD CHAMBER (aluminum) machines: MACHINE SIZE Locking Force Distance Between Tie Bars Shot Weight KN ton mm inch kgs lbs 100 ton x384 15x ton 400 ton 600 ton 800 ton 1200 ton 1600 ton 2000 ton 2500 ton x508 20x x610 24x Shot weight is based on Aluminum alloy x737 29x x914 36x x x x x x x x x Average Specifications of HOT CHAMBER (zinc) machines: MACHINE 50 ton 75 ton 100 ton 150 ton 200 ton 250 ton 300 ton 350ton 400 ton SIZE Locking Force Distance Between Tie Bars Shot Weight KN ton mm inch kgs lbs x x x x x406 16x16 Shot weight is based on Zinc alloy x x x x x x x x x x x x Die Casting Machine Buyer s Guide Copyright 2016 Jack Iwanski

15 WHICH IS THE RIGHT SIZE FOR YOUR SPECIFIC PROJECT? Most die casting projects fall into one of these two categories. This is a simplified explanation, but it covers most projects you will encounter. This table explains how to find the right machine for a specific project. Project Categories: PROJECT TYPE New Die Existing Die HOW TO FIND THE RIGHT SIZE OF MACHINE If it is a new project and no die has been made yet, then a local die maker will be the best person to tell you the shot weight and size of the final die. Once you have that information, he will be able to suggest to you the size of machine needed OR you can use the charts on the previous page. If the die has already been made and has been run by someone else, the owner of the die can tell you the size of machine that was used. If not, then perhaps you can look at the drawing of the die and then consult with a local die maker OR you can use the charts on the previous page. WHAT IS THE ESTIMATED PRODUCTION OUTPUT? This question is a somewhat more complicated question to answer. But there are guidelines which help greatly. Most die casting machine manufacturers (not all) provide dry cycle times for their machines. A dry cycle is the amount of time needed for the machine to perform the whole casting process from bringing to end WITHOUT molten metal being added and WITHOUT cooling time of the casting. Generally speaking, the larger the machine the slower the dry cycle time. The reason for this is that larger castings are made on larger machines. The smaller the casting, the less time it needs to solidify and so the cooling time (also known as set time in some parts of the world) become less of a factor. With very small castings it is not a factor at all. It all depends on the casting size and weight. It is not possible for die casting machine manufacturers to give figures for actual cycle time without sufficient information about each proposed casting and the amount of cavities in the die. However, these figures are obtainable from either a die maker or by using die casting simulation software and vary greatly from project to project. Such figures are important because they will tell you how much time it would take for the casting(s) to solidify in the cavity(s) after injection and before the machine can open the die and the casting(s) can be removed. So, as you can see, at best, die casting machine manufactures can only provide dry cycle times. Die Casting Machine Buyer s Guide Copyright 2016 Jack Iwanski

16 To calculate the actual cycle time you will need to add cooling time to the dry cycle time provided by the machine manufacturer. Here is a simple way to calculate Estimated Production Output using only dry cycle times, (but be sure to add cooling time to get a Final Production Output figure). EXAMPLES: The following examples are based on a die casting machine which has a 4 second dry cycle. Keep in mind this is only theoretical and does NOT include cooling time. ESTIMATED PRODUCTION OUTPUT CALCULATION (Dry Cycle) - SINGLE CAVITY DIE ===================================================================== 60 seconds (1 min) divided by 4 sec. = 15 castings per minute 15 x 60 minutes = 900 castings per hour 900 x 8 hours = 7,200 castings per 8 hour work day ESTIMATED PRODUCTION OUTPUT CALCULATION (Dry Cycle) - 4 CAVITY DIE ================================================================ 60 seconds (1 min) divided by 4 sec. = 60 castings per minute 60 x 60 minutes = 3,600 castings per hour 3,600 x 8 hours = 28,800 castings per 8 hour work day WHICH IS THE RIGHT BRAND? There are many manufacturers of die casting machines in the world. However, our many years of experience have shown, over and over again, that the best quality machines are recognized brand names manufacturers and originate from North America, Europe and Japan. As well, do not be too focused on the age of the machine. Due to their construction, and unlike most machines, die casting machines last a very long time. In addition, the technology has not changed too much over the years. Unless you plan to make very high end castings, most well made used machines should be sufficient for most applications. There are some good deals to be had slightly older machines. Die Casting Machine Buyer s Guide Copyright 2016 Jack Iwanski

17 WHAT IS A REALISTIC BUDGET? While of course, everyone would like to spend the least amount of money on capital equipment such as a die casting machine, generally speaking, you can use the follow basic guidelines when it comes to comparing prices of new and used machines. The reason for the price range of secondhand machines is the age and the condition. Price Comparison (Secondhand to New): SECONDHAND MACHINE TYPE Secondhand Machine Brand Name - Good Quality Secondhand Machine Brand Name - Good Quality NEW MACHINE TYPE New Machine Brand Name - Good Quality New Machine Off Shore - Low Quality - Disposable PRICE OF SECONDHAND COMPARED TO NEW 10% to 30% of new price 40% to 60% of new price This comparison takes under consideration the cost of machine plus cost of automation equipment and shipping. SOME EXAMPLES OF USED AND NEW MACHINE PRICES: 460 ton Buhler Price Used: USD $ 65,000. (1991) Price New: USD $ 500,000. (approx) 650 ton Toshiba Price Used USD $ 85,000. (1994) Price New: USD $ 600,000. (approx) Die Casting Machine Buyer s Guide Copyright 2016 Jack Iwanski

18 WHERE SHOULD YOU BUY A USED MACHINE?: When considering the purchase of a used machine, ultimately you have two basic choices. BUYING PRIVATELY: The first choice is to buy privately from a die casting company. However, when you think about it, this choice is very often limited, actually more so then you would expect. First of all, by calling from die caster to die caster it is hard to locate the right machine for your needs. Secondly, there are used machinery dealers like my company, in which it is their business to call and keep in contact with all die casters on a regular bases and find out if they have machines for sale. For example, our company is in touch with just about every die caster on the planet. When we do find a good machine, we snatch up before it even sees daylight. Therefore, your chances of finding a good machine just phoning around becomes very remote. BUYING FROM A DEALER: The second choice you have, is to buy from a die casting machine dealer. There are two types of dealers in the world stocking and non-stocking. No-stocking dealers accumulate lists of machines available for sale. They offer these for sale to everyone and they usually make about 10% as a selling commission from the owner of the machine. There are 3 problems with this type of business model; 1) Non-stocking dealers sell machines that they have not purchased with their own money. As such, they take no responsibility for these machines. They basically sell and run. 2) Non-stocking dealers have no stock on hand and so they can disappear very quickly. They have no big, heavy machines to move which takes time, effort and money. 3) Non-stocking dealers offer machines that a stocking dealer like my company already passed up or refused to purchase. When we pass on a machine there must be a very good reason. Non-stocking dealers usually offer the leftovers after stocking dealers pick over the good ones. Die Casting Machine Buyer s Guide Copyright 2016 Jack Iwanski

19 Here is an example comparing a Non-Stocking Dealer to Stocking Dealer; Non-Stocking Dealer Offers Leftover Machines - Does not invest any of his own money in the machine. - Takes no responsibility in after-sale. - Here today (but can disappear tomorrow). Stocking Dealer Offers The Best Machines - Invests own their money in the machine. - Takes pride in responsibility in after-sales. - Business is built on long term relationships. MORE INFORMATION: As mentioned this ebook is a work in progress. If you would like more reference material, check out these links; Learning Center: An assortment of educational videos and other die casting related information intended to further understanding and knowledge about the die casting business worldwide. Business Center: Various articles that are presented in the form of short "series" that are designed to help you improve your business and to avoid many of the pitfalls that are common in business and especially the die casting business. Machine Inventory: A huge selection of machines in stock and ready to go. Die Casting Machine Buyer s Guide Copyright 2016 Jack Iwanski