Thursday, June 14, 2007

The Hammer and Pry Bar Incidents

HammerAs with any CNC machine, and Excellon is no exception, it is wise to make sure operators keep the hammers and pry bars away from the table tops.

Operators seem to continually try to challenge the structural integrity of the machines by placing tools on top of the tables or in the path of machine carriages and powered XYZ assemblies, and then decide to hit the park button or typing a high speed jog command into the keyboard. Loud thumps can be heard clear across the production floor. More than one machine has taken a crash over the years. Actually, this type of crash is a very common occurrence in the life of a drill and rout cnc machine. Even cnc milling machines and other types of automated servo controlled equipment and robotics have been known to take a hit or two from someone leaving a tool on the table or getting it wedged between the XYZ moving parts.

Excellon Mark VIWhen the Excellon drilling and routing machines only had spindles to contend with, on the z axis overhead assembly, a crash was much easier to deal with. Simply placing an alignment pin in the nose of the spindle and going to the magic number locations to see if the spindle was out of alignment for tool changes was the thing to do. However, with the advent of multiple tool magazine holders, a crash involving the tool cassettes requires substantially more work to verify the alignments of not only the spindle, but also the alignment of the tool magazine assembly and the transfer piston assembly.

Other precision hardware components can also end up heading for the trash can when a crash of this magnitude occurs. For example: key pressure feet components, used for precision depth control, have been known to become bent and inoperable. Many of these incidents can result in excessive down time, expensive part replacements, and time consuming service calls.

Make it a drill room policy to remove that hammer and pry bar from the drill table before the machine is moved. Better yet, don't place it down on the drill table surface to begin with. Your machines will appreciate implementing this policy plus the company will not have to pay for as many service calls. The bean counters will love it, we guarantee it.

Contact Probe Industries, Inc., Your Machines' Best Friend

Addendum to the Story

In recent news, was a machine that the operator left the hand tools on top of the granite surface and proceeded to hit the park button, jamming the tools against the front cover and underneath the table top. This caused one of those loud thud sounds in the drilling production room, and also lifted the table several inches above the proper position. Several precision air shoes popped off their mounts. However, this was not the worst of the problems.

The y axis Heidenhain scale was crashed. The read head encoder portion of the scale was bent in the middle, and the machine alignment blocks were knocked out of alignment. The machine was KO'd for the count.

Several thousand dollars latter in new parts and labor, along with some extensive rehab time were necessary to get this machine rolling along again.

So, be careful where you place your tools.

Thursday, May 24, 2007

Maintain Those Air Compressors And Air Dryers

With the cost to purchase new drilling and routing machines at hundreds of thousands of dollars, it makes economical sense to provide oil free, and dry air to the equipment.

With the new synthetic oils being used to lubricate the internal mechanical parts of compressor systems today, many overlook the fact that these oils that help compressors run efficiently are the same oils that contaminate and destroy the rubber "O" rings, seals, and solenoids used throughout the entire manufacturing facility when compressors are not functioning at top performance. Many times, years later, equipment that has been run with contaminated compressed air will have a life long list of problems that seems to never go away.

"O" rings and seals are not the only items that can become damaged with poor air quality. The air hoses themselves can become rotten from the inside out. Many of the synthetic oils actually breakdown the rubber hoses to the point where they become super soft in which blowouts are common. These blowouts can occur in the most difficult to reach areas on a machine and can cost the owner thousands of dollars to repair.

Contaminated air can also affect the surfaces of the machines. Many of the drilling and routing machines function with the moving parts floating on a very thin cushion of air. The X Y tables float on air bearings, very similar to how an air hockey puck floats on an air table. The table on many of the PCB drilling and routing machines are made of solid granite, with air shoes mounted on the carriage or overheads. Micro-holes are drilled into the air shoes to allow the air to come out in a small stream, causing the air bearing or air shoe to float away and lift from the surface at a fraction of an inch lift. This type of lift provides very little resistance, and allows the machines to quickly accelerate and operate at very high inches per minute surface feed rates. As little as ten years ago the maximum feed rate speed for the machine movements was 400 inches per minute. Now, it is not unusual to be moving the X Y tables at over 2000 I.P.M. With that type of high velocity movements, air shoes that are contaminated by poor air will result in a very expensive mechanical crash that can destroy both the air bearing and the granite surfaces. In extreme cases, air contamination has resulted in an early death of cnc PCB machines. In the best of cases, where problems are spotted early enough, granite repairs are required to fix the machine surfaces. If the air shoe is only replaced, and the surfaces are not repaired, the new air shoe will fail quickly, because of lack of lift over the damaged areas.

Oil in the air is not the only problem that can have devastating affects to facility equipment. Water is the other contaminate that is not good for any of the equipment. We can't tell you how many times we have seen compressor people come out to work on the compressors, but haven't a clue about the air dryers. First off, an air dryer works on the chilling down of the air to a dew point. It's at this dew point that the water in the air condenses, and turns from a gas to a liquid. If an air dryer is not chilling the air, then the water does not condense at the dryer, but condenses in the air lines leading to the machines and in the machines. Here is a very easy test that anyone can do to quickly determine if an air dryer appears to be functioning properly. Simply feel the incoming air line at the dryer and then feel the outgoing line at the dryer. The outgoing air should be significantly colder than the incoming. If both the incoming and outgoing are the same temperature, it is likely that the air dryer is not function properly. Potential reasons are that the freon compressor system is not working or the cooling fans are faulty.

The following is an example of the amount of moisture content of saturated air.
1000 Cu, ft. of saturated compressed air at 100 psi and 120° F. contains 10.9 fluid ounces of water in the form of water vapor. This same quantity of air when cooled to 60° F. at 100 psi contains 1.58 fluid ounces of water vapor. The difference between the two figures, or 9.32 fluid ounces, is released from the air in the form of liquid water and must be removed from the system with a suitable filter to prevent its passage into air tools, bearings, cylinders or other pneumatically serviced devices. The quantity of water which must be removed from the compressed air system is directly proportional to the amount of compressed air passing through the system. Therefore, in a system supplying 500 cfm, the quantity of liquid water to be removed would be 500/1000 x 9.32 or 4.66 fluid ounces per minute. If the system handled 500 cfh, the quantity of moisture to be removed would be 4.66 fluid ounces per hour.

Lack of proper air pressure and volume can also affect the machines. Many customers over the years have had misconceptions of what the actual air pressure and air flow (measured in scfm) are required in printed circuit board, CNC machining, manufacturing, and fabrication production facilities. Instead of viewing the pressure at the machines, customers are making the mistake of only monitoring the pressure at the compressor itself. There are significant line losses to contend with. Depending on the pipe diameter, it is not unusual to see a change of 5 to 10% air pressure reduction per 100 feet of straight pipe. Add to that, 90 degree and 45 degree elbows, valves, filters, and air dryers, the loss of pressure and flow volume can be even more pronounced. Additionally, the maximum amount of flow through any pipe size is topped out at a certain pressure. This means that a pipe that is too small can only handle a certain amount of flow volume. If you have three machines in your drill room that use 30 SCFM each, and only have a 3/4 inch air line from the compressor to the drill room supplying 100 lbs pressure, the maximum flow volume is only 80 SCFM through the pipe. Add to this the loss of 5 to 10% from the pipe and fittings and you can quickly see that you will not have the volume and pressure to maintain the operation of your equipment. Refer to chart below. Click to expand and open in new window.

Air Pressure Chart
With new equipment being able to drill smaller holes, at higher RPMs, with tighter tolerances, and using air bearing spindles, the quality and quantity of the air supply will be of paramount importance for keeping those machines running for a long time in the future. Protect your equipment investments and invest in a quality, dry, oil free, compressor system today.

If you need help with down machines, preventative maintenance programs, and equipment analysis give us a call today. We are available to travel anywhere in the world.

Contact Probe Industries today.

Sunday, April 15, 2007

Measuring TIR Spindle Bearing Runout On Your CNC Machine

Spindle Runout Problems Can Be Your Hidden Quality Issues In Building Reliable Printed Circuit Boards

The simple definition of spindle radial runout is how much wobble a spindle produces at the nose. Axial runout is the measurement of how much play there is perpendicular to the axis of rotation. The reading is represented by Total Indicated Runout, TIR, which means the distance measured between the largest plus direction and the largest minus direction for a total indicated amount. A spindle can be measured either dynamically (at speed) or statically. The dynamic measurement is by far, the most accurate and requires special non-contact measuring devices.

Today's air bearing spindles have gotten faster with higher precision than the ball bearing spindles of the past. Air bearing PCB spindles can typically be found running in the 120K RPM through 180K RPM ranges, with some spindles running up at 300,000 RPMs. Since the spindle air bearings are floating on air, no mechanical contact is made with the rotor. Radial and axial runouts can be maintained with very tight precision. Westwind, a manufacture of high speed air bearing spindles claims total indicated runout accuracies of their PCB drilling spindle of less than 10 microns: "Typical synchronous radial runout values: < 10 microns (PCB drilling spindle, high speed)," which equates to approximately, less than .0004 inches TIR.

High Speed Spindles
High Speed Spindle Chart Courtesy of Westwind Air Bearings
Chart shows maximum spindle speeds in different market sectors

Many of today's CNC PCB drilling machines incorporate laser measurements for checking runout of the spindles at operational RPMs. However, this does not always tell the whole story. Many times the machine's software is set at a very nominal level of warning for telling an operator that the runout of the spindles is too great a value. The result is the machines may be drilling with less than desired accuracies for the hole locations and even the hole quality can be affected by runout related problems. This is becoming an even greater issue as today's circuit boards are becoming much denser, with tighter tolerances required between the holes and the traces, and the continued direction toward smaller carbide micro drills (.008 .20mm - .004 .10mm) and more concentrated holes. Other times, spindles with excessive axial play (end-to-end) will result in depth problems when trying to drill in a controlled depth mode, such as drilling blind vias where a certain depth has to be maintained within a thousandth or two, and hole quality issues when drilling standard holes.

The overall runout is not only affected by the quality of the spindles themselves, but factors such as collet wear, collet cleanliness, and collet adjustment will greatly affect the TIR reading. Collets wear out due to constant opening and closing movements which does produce wear upon the rubbing surfaces. These wear marks become increasingly more visible over time. Additionally, circuit board vacuum debris will cause wear and dirt issues which will result in poor TIR readings. Collets that have reached the end of their life cycles can sometimes be spotted by looked at with the naked eye or a small scope. This however, will not always show a problem with a collet. Sub standard collets are a particular problem today. As PCB manufacturers have attempted to cut costs, they have gone with cheaper collets that do not always measure up. Operator collet adjustment and cleaning maintenance training is another area where many circuit board manufacturers' personnel are lacking. In an effort to constantly cut costs, new drilling operators are hired with limited knowledge of how to properly clean and adjust spindle collets. This results in a total reduction in overall quality throughout the whole circuit board manufacturing processes.

Additional factors that contribute to spindle runout and spindle air bearing failures are the air supply quality and the stress spindles receive due to excessive drilling forces, through improper feeds and speeds. Excessive chip loads for large diameter holes can cause the spindle air bearing surfaces to collapse and become internally damaged. Spindles that turn at very high speeds produce lots of air friction. This friction generates heat which can cause early failure of the spindles. Clogged coolant passages, because of improper coolant system maintenance, can also be a factor for excessive heat generating issues and spindle failure. Ambient air temperatures in the drilling rooms can also greatly affect the life of the spindles. Extreme temperatures, both on the cold as well as the hot side can result in spindle failures. Manufacturers that insist on running their spindles at maximum RPMs are likely to see a reduction in the life of the spindles. Just because a drilling spindle can run at 180K RPMs does not mean that it should run constantly at those speeds.

Equipment Used To Measure Total Indicated Runout, TIR

Lion Precision is a company that manufactures a dynamic non-contact capacitance runout measurement meter that is ideal for measuring spindles at all speeds. With a dynamic indicator, a technician can precisely tell the condition of the spindles, collets, and the runout, at the typical distance from the nose of a spindle, that a drill tool would actually be developing at spindle RPM.

TARGA III Dynamic Runout System Lion Precision

The non-contact measurement from Lion Precision is top of the line equipment. Probe Industries has used Lion Precision equipment for many years on all types of drilling, routing, PCB, milling spindles, various machine shop equipment and other applications for measuring the total indicated runout for high precision equipment. We have seen equipment that was suspected to have all types of positioning problems with linear scales or rotary encoders, turn out to be a spindle runout problem all along.

Circuitree MagazineBe sure to sign up for the PCB industry's Circuitree magazine subscription in which a more in-depth spindle runout article is published in the August 2007 Circuitree issue, with additional information and a detailed description of how to measure spindle runout, along with all the procedural controls for QC to implement for the production floor. Don't miss it, your quality control depends upon it.

What Probe Industries Can Do For You

Probe Industries can evaluate your current machines and let you know what the status of each of the drill and rout stations are. We can check the spindles at all RPMs and produce detailed charts of the condition of your spindles. The result of getting a complete spindle inspection will let you know which spindles are good and which ones are bad. You will no longer be drilling in the dark. Your scrap rate will be reduced and your quality will improve. We can provide technical training for your quality control department. Probe Industries can also help out the CNC machining company that is interested in finding out the overall runout of their ball bearing spindles on their milling machines.

Contact Probe Industries for a detailed Spindle Runout Report for your machinery and equipment today. We also provide maintenance and repair services for all types of equipment.

Probe Industries, Inc.

We have over 28 years of service experience in maintaining and repairing Excellon Machines, Kennard, PDA, Pluritec, Hitachi, Mania, Klingelnberg, Advanced Controls, Trudrill, ESI, Dynamotion, ATI, and other PCB drilling and fabrication equipment, plus a wide variety of service experience on other types of machinery and equipment used in various industries.

Also, be sure to have us check out that piece of used equipment before buying from an auction or other company. Read about The Tale of the Uninformed Used Equipment Purchase.

Friday, April 13, 2007

Checkout Used Excellon Equipment Before Buying

Everyone wants a great deal on Excellon machines or any used equipment. With many circuit board shops closing down, and their equipment being auctioned off, it is wise to have the machines checked out before buying.

The Tale Of The Uninformed Used Equipment Purchase

Excellon, Kennard, PDA, Pluritec, Hitachi, Mania, Klingelnberg, Advanced Controls, Trudrill, ESI, Dynamotion, ATI, Wessel, DAC, and other PCB drilling and fabrication equipment, that supposedly were running before being shut down have cost thousands of dollars to the unsuspecting buyer when buying blindly online through an auction or even the buyer looking at the machine in person. Instead of having a qualified and experienced service technician inspect the machines, buyers go it alone. Buyers think they are getting a great deal, but many times what they are getting is a big boat anchor. The outside of the machines can look all beautiful and cleaned up, while the inside is falling apart.

We have seen machines that looked like they have gone through an acid bath, with components being etched away on the computer circuit boards, heat exchangers that are corroding, lead screws that have never been maintained, clogged coolant passages, air systems that had pumped years of oil and water to the machine, air shoes clogged, granite damage, air bearing or ball bearing spindles that are frozen, and general lack of overall machine maintenance.

At best, many of these issues can cost thousands of dollars to repair. At worst, the repairs are so cost prohibitive, that it would cost more than what the machines are worth. The auctions are only one part of the problem going on today.

Here is a list of some of the most common used Excellon Drilling and Routing Machines on the market today.

Excellon Drilling and Routing Machines

  • XL 3
  • XL 3 DR
  • EX 110, EX 110 DR
  • EX 200, EX 200 DR
  • EX 300, EX 300 DR
  • XL 5, XL 5 DR
  • Mark IV, Mark 4, Mark IV DR, Mark 4 DR
  • Mark V, Mark 5, Mark V DR, Mark 5 DR
  • Mark VI, Mark 6, Mark VI DR, Mark 6 DR
  • Mark VII, Mark 7, Century
  • Uniline
  • System 2000, System 2001
  • Excellon and Kennard Routers

Optical Machines

  • Opic

Used Circuit Board Equipment Dealers

Used equipment dealers have notoriously made a bad name for themselves over the years. We have even heard that China got so ticked off with some of the junk that was being dumped into their country, that they put a stop to it and started buying new equipment as a matter of policy.

The 1990's were the golden years for the printed circuit board industry in the United States. This was the time where everyone was going after the latest and greatest equipment available. When the new machines could not be delivered quickly, many of the circuit board shops looked to the used equipment market to tide them over. Many of these machines were beat down in the late 90s and early 2000s. So, now a lot of the equipment has numerous issues to contend with.

To be fair, not all used equipment dealers are shysters. Some rebuilders of circuit drilling and routing equipment do a fairly good job. They do more than just putting on a new coat of paint. Some will offer extended warranties for both parts and labor. Still, it is wise to invest in an impartial inspection of the equipment before, in ideal circumstances, or even after the drill or routing machines have been installed from a dealer that is giving you a warranty. This way, you can make sure everything is right, while the machines are still under warranty.

Contact Probe Industries today to have a scheduled checkout. We are available to travel anywhere in the world. Get in touch with us today.

Thursday, March 29, 2007

PCB Routing And Fabrication Machine

Watch a 4 spindle Excellon Mark 5 DR (Driller/Router) routing a stack of printed circuit boards. See how the automated process works.

Circuit boards are typically manufactured in a step and repeat layup, and held in place on the machine with tooling pins through the circuit board and into the soft tooling plates. Stack height varies depending on board thickness and material type.

Cutter bits for cutting PCBs are typically solid tungsten carbide, with a diamond cut geometry design. Table feed presented in the video is typical for a .093 inch diameter bit.

For more information related to service, maintenance, repairs, and preventative maintenance go to Excellon Machines. For informative articles related to drilling and routing, take a look at the postings published at Probe Industries Blog. Read the article: Understanding TIR and Measuring Spindle Runout. To get help with all your drilling and routing equipment service needs contact Probe Industries today.

Sunday, March 4, 2007

History Of Circuit Board Design

Great Article in Circuitnet From an Insider Perspective On The History of The Circuit Board Industry

Striving for Functionality: Ralph Robinson and the Beginnings of PCB Manufacturing in Northern California

In the mid-1950's, 'printed circuit' manufacturing technology was in its infancy, so much so that even though the manufacturing techniques were evolving, the available materials were not up to snuff. It was nearly impossible to build working circuit boards in any volume, certainly not enough to make any money on it.

Article in Circuitnet

This article gives great insight into the early days of printed circuit boards. If you ever get a chance to talk with Ralph Robinson, he is a great guy and can probably fill a ton of books with all the stories and information about circuit board manufacturing.

Probe Industries, Inc. Drilling and Routing Machines Repairs And Maintenance

Wednesday, February 28, 2007

PCB Drilling Machine

Watch A Single Spindle Air Bearing Excellon EX 110 DR Driller/Router Machine Drilling Circuit Boards

Probe Industries, Inc. is a full service PCB CNC Machines Repair And Maintenance Company. We are available to travel anywhere in the world to fix or maintain your machines. Contact Probe Industries on the web today.