It's common knowledge that the industry buzz is ever shortening leadtimes and there is a lot of expensive equipment out there for moldmakers to machine at high speeds to shorten delivery times. But what's the small to midsize shop to do if it wants to utilize this technology but cannot afford the capital equipment purchase?
The answer: just ask Mark Mills. This owner of a two-man shop - Cherub Technologies (Elkhart, IN) - knows a thing or two about high-speed machining, and he didn't have to make a major purchase to get this information. Rather, Mills embraces a philosophy of taking baby steps to achieve success - in other words, his shop is growing in stages, and by making little changes in his machining methods, he is able to mill precise contours with lighter cuts at high feedrates - all at 10,000 rpm!
"It's great to have high-speed machining equipment when you are ready to afford it," Mills states, "but in the meantime, moldmakers should know there are steps that can be taken to get there." Mills describes his equipment as "universal" - it must be able to tap, drill, rough and finish. "I'm not a big corporation," he comments. "I can't buy a million dollar machine that does nothing but roughing. I need to be able to do it all."
Steps for Success
Mills wants to share his formula for success with others, and explains in detail how he has gotten the most out of his machining center combined with the right choice of quality tools to achieve the highest standards of quality and efficiency.
Step One - Setup
According to Mills, the first step a moldmaker must take to machine at high speeds without having to purchase a fancy piece of equipment is to reduce setup time. "Everybody can do it and it doesn't cost anything," Mills notes. "You have to go in stages. Setup time is the time you start a project to the time you stop the project. You have to understand what you are doing and don't look at the big picture. When you do that it becomes so overwhelming. Break everything down into smaller stages - the time it takes for someone to square the steel, the time the steel sits on the floor - can any of this be reduced? Work on the steel as soon as it's in-house. Start with the manufacturing end of the job. The management end is a whole other ball game."
Step Two - Documentation
Mills practices a simple philosophy when it comes to documentation: "Say what you do, do what you say and document it. It makes a lot of sense if everybody understands what's going on and anyone can pick up the ball at any time and just follow a machine. If someone gets the steel off of the shelf and knows that it has to be squared or drilled, write this information down so that anyone in the shop knows where it is going next. Then there is more control over what is going on; and if a machine is open it can be utilized faster."
Step Three - Upgrade Your Equipment
Mills recommends looking at high-performance drills. "There are thousands out now," he states. "They are an investment just like any machine and they give you two to three thousand holes at one-tenth the time that it takes you to do a normal drill hole. This is how cycle time gets reduced a little bit at a time. If you can reduce your drilling time from a half-hour to five minutes, how long does it take to pay for the high-performance drill? Not very long. Think about your long-term investment and results."
Step Four - Roughing/Contouring
Once prep time is reduced, setup time for contouring also must be decreased, Mills notes. "This can be done by using a magnet, a fixture system, dowel pins or a combination of all three," he says. "The goal is to be more efficient because we don't have the manpower to do everything.
"It's important that everyone works together," Mills continues. "The steel is ready to be roughed, so someone has to put the steel on the machine. At that point, he goes to his CAM software and produces his roughing program. It's good to work with software that you can program ahead while you are setting up the machine. It must process fast and have a basic format so that all operators will feel comfortable on it."
Mills summarizes the process while recommending the buddy system: "Let's say there are two of us. When the steel comes in the door, you grab it and put it on the machine that drills the holes. While you are doing that, I get the IGES file and produce the roughing paths. So you've drilled it with the high-performance drills and I have the roughing program. Now you go ahead and take that piece of steel and put it on the machine for contouring. At that time, I get ready and grab another piece of steel that has to be drilled. The part that's being contoured is roughing and I either have another piece of steel ready to go onto another machine - or that machine - and you go ahead and start programming the next toolpath for the next piece of steel. Now the work is flowing nicely between the two of us.
"We don't have a programming department that doesn't understand what tools we have or how we secure the steel, so we've eliminated a big communication gap," Mills continues. "I feel if we bring the programming down to the floor in a controlled manner, we will be successful - but everything must already be planned: What types of tools do we use in our roughing? What are the parameters behind that tool? Everyone in the group needs to be on the same page so there's no guesswork."
Step Five - Semi-Finish and Finish Passes
According to Mills, since roughing is 25 to 30 percent of the mold build process, it's time to either get additional machines roughing or start to produce the semi-finish and finish passes while the steel is roughing.
"When we quote a job, there might be five hours for programming, 10 hours for machining, then 10 to 15 hours for bench time (polishing and assembly)," he states. "What we've done is take our 10 hours of machining time and included our programming time. We've already cut off a third of our overhead. So while it's machining, the operator is producing the semi-finish and finish passes. Then while it's running, he can get the tools prepared and set in their holders, and make sure he has all of the tools - the whole nine yards.
"At that point the moldmaker needs to decide if it's better to use a higher quality carbide tool," he states. "For example, if the machine capabilities for finishing are 110 inches per minute, that's all he has. So, will he want to use a tool that will go 50 or 60 inches a minute or one that will actually utilize what the machine is capable of? In other words, does it make more sense to stop and change tools on a cheaper carbide tool or to spend a little more money on a better tool that will last longer?
"My ball nose endmills cost me $160, but at 10,000 rpm I'm able to go 180 inches a minute," Mills continues. "My competitor is going 40 inches a minute with a cheaper tool. What takes him four hours takes me one hour. So, when you buy a higher quality tool, it's not the price of the tool, but what you are actually saving with that tool. Also remember that this tool will cut better and give you the benefit of reduced bench time. Instead of buying four machines next week because you have all of this work to do, what if you can make each machine four times more efficient? We are increasing our capacity fourfold by using something we can throw away, and not having to increase manpower. So maybe it's not necessary for us to buy that machine or buy a new building until we are ready."
These little tricks will allow moldmakers to get more money, Mills emphasizes, which will give them the ability to expand and/or buy more equipment when the time is right for them.
Man With a Plan
Mills has had nothing but success employing his techniques. "I've reduced my cycle time, increased my profit margin and increased my capacity," he asserts. "At what point doesn't this sound good? If I produced everything 50 percent faster, but quadrupled my tooling costs, in the end, when all of the numbers came out in the wash, my profit margin was the same, have I done badly? No, because I have six months of the year left. I've produced in six months what I normally would over a year and I have still been able to keep the same profit margin. That leaves me six more months to either make profit or to get more customers."
Mills plans on sharing the wealth through a new website, www.cherubtech.com, which will teach the everyday moldmaker how to achieve similar success. "I love to teach and that's what the website is all about," Mills explains. "People can log on and there will be a machining process demonstration - like roughing or finishing - and they will actually be able to see what is going on and get an understanding of how it's done. People need to understand why this works, so they can do it themselves and explain it to other people.
"First, I will describe how the part will be machined," Mills continues. "Then, I will explain how the machines were programmed. The third part will be the machining portion and the final part will cover what it cost, time saved and how it can be justified."
Everything will be prerecorded and put on the web digitally so it can be seen throughout the month. Then, people can respond via e-mail with questions and tell Mills what they'd like to see next. "The next demonstration will pop up based on those e-mails," he says. "Whatever anyone is having a problem with, I will formulate a demonstration that shows how that problem can be solved - with the help of friends from around the world, of course."
The online tutorial is available for a fee, Mills says, but "if a moldmaker can save purchasing three carbide cutting tools a month, the class will be paid for." Mills wants the website to serve as a stepping stone for others to achieve the same success he has. He concludes with this final piece of advice. "I have replaced my standard controller with a Creative Technologies control," he says. "I use WorkNc to program my 3-D shapes and I use Jabro tools from CW Vordenberge Co. Why? Because of support that they have all offered me - period. Although we can show improvement with any one of these tools (control, carbide and software), it's a combination of all of them that will show the biggest gain. This will be practiced worldwide in the upcoming years; and with the use of the Internet it will spread faster than we ever thought possible. If we wish to compete in this world market we better prep our people with thoughts of how to reduce leadtimes and cost, or someone else, somewhere else, will."