Posted By: Andy Kamashian | Posted On: December 11, 2018
Understanding the "CNC" of Press Brakes
As a used machinery dealer I am often asked my opinion about the viability of purchasing a new Press Brake when considering trade-in equipment. Many buyers believe that their needs are for only a "simple" control and gaging system and somehow have it backwards when it comes to the Computer Controlled CNC gaging systems offered. Most machine manufacturers offer a variety of controls for their press brakes currently offer 4 systems on their machinery described as follows:
Simple PLC Controller - Controls only the RAM - No Gauging at all
Advanced PLC Controller - Ram and Single Axis Backgage Control only (Y and X) Effective yet only repeats positions given input, typically not "Programmable" from outside sources.
Graphical/Interactive CNC Controller - Multi-Axis Gaging System with Graphical Programming, Offline Programming and Networking Capabilities) The most popular option and the one addressed here.
With these various options available many buyers "shoehorn" themselves into a very limited control and are often hesitant to "move-up" to the better controller out of fear that it will be harder to learn and operate as well as not understanding what they will gain with the increased investment. Below I have detailed the many discussions that I have had with buyers as to why the a Graphical CNC Controller is not only a wise investment, but a necessity on their new press brake. Now remember, I am a used machinery dealer. I buy and sell used machinery. However the reason I provide this information is to assist you in making the right decision on your new press brake and gain your future business when it comes time to trade or sell your machinery as these machines are a primary focus of mine.
1) Operator vs. Fabricator Simple PLC Controller:
Your press brake operator is typically an $10-12 per hour guy, part time, college student etc. Whereas your Fabricator is typically your lead man or foreman and is in the $18-22 p/hour category or more. So financially it makes sense to move as much work as you can from your Fabricator to your Operator.
A Graphical/Interactive CNC Controller does exactly that.
On any PLC type control, the setup man needs to know the values AND order (bending sequence) of all the positions of the ram and the backgage. He will also need to know the bend deductions for the material in use, calculate the flat blank size and individually input each and every position that the back gage and ram need to make (Clear, Approach, Pinch, Bend Depth, Return etc.) Your operator won't know these values or even what they mean, but your Fabricator will. So therefore your forced to let your head fabricator be your press brake setup man while your operator stands around waiting.
So let's do some simple math:
Average calculation time to setup a press brake with a part making 2-3 bends is 15 mins. Average input time 10 mins. Average bend test (part scrap) time 10 mins. Total setup time 30-35 mins (keep in mind that cost you $10-$12, not counting taxes and insurance, of your head guys time and most likely $5 per hour of your operators time while he stands around and waits for the brake to be setup) not to mention 30 minutes of non productive down machine time.But there are other factors to consider:
Once a PLC Controller has been programmed the average bend test time is is 10 minutes with adjustments and changes. Once a part is bent, it can't be effectively re-bent as "springback" is different so there are typically 2-3 scrapped parts for every re-bent part. Multiply that by 3-4 bends and you've got a good pile of scrap in the bin at the end of the day from all the "test" bends you have needed to make to ensure the calculations and bend sequencing was correct. Note: Typically SCRAP alone can pay back the cost difference of Quality CNC Graphical Controller in just the first 4-6 months.
Network-ability and Offline Programming:
The PLC based controls, do not allow for networking to your server for direct control of offline and archived part programs. Therefore the only way to save a part program is within the memory of the on board PLC. Networking can be the key to ensure your operator is running the right revision of parts instead of the last program he thinks is right. Your selling "Revision F" and your Operator is bending 100 pieces of "Revision D", that ever happen? Again, the Graphical CNC Controllers reduce scrapped parts, wasted machine and shop time by ensuring the capability to run the most current part programs as controlled by engineering or management.
A typical quality Press Brake maintains a good resale value as they are a very common tool for almost any shop. However a machine equipped with a Graphical/Interactive CNC Controller can bring not only 15-25% more for the machine but can move the machine in a very short period of time as they are very desirable controls for all the above reasons mentioned. Although resale value may not be immediate consideration it should be important to your decision making process as a high resale value is important for trading in/up the machinery for growth or for an outright sale should a downsizing be required, or your bending needs change in the future.
Unlike resale value, Asset Value pays you back when its time to obtain financing against your assets including property. Press Brakes with Graphical/Interactive CNC Controllers will be of higher asset value and thus could be solid financial decision should a loan against them and their value be required, and all while they remain in plant and under power making you parts and money.
Your investment in a quality Press Brake is a secure one whether buying new or used. The addition of a Graphical/Interactive CNC Controller makes it a very profitable and secure one as well. They are far easier to run then you might imagine, calculate hundreds of factors while providing a graphic of the outcome, requires less operator and fabricator skill, reduces scrap and holds the highest resale value. If your buying Press Brake, new or used, do yourself a favor and add the Graphical/Interactive CNC Controller option.
At Southern Fabricating Machinery Sales, Inc. we are experts in Press Brakes and Metal Forming. We understand the process, the materials, the tools and the products available to make your forming project a winning one. Whether your considering a quality used system or looking to add brand new capabilities to your shop Southern Fabricating Machinery Sales is the right call to make . Call us at 813-444-4555 or email email@example.com for more info.
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