Frequently Asked Questions
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Why are the VPI scribers the most popular equipment in the world for production of Liquid Crystal Displays?
Answer: Our scribing equipment is the only glass scribing equipment specifically designed with precision glass scribing technology in mind. See Factors Affecting Scribe and Break Yields in Flat Panel Display Manufacturing for a technical discussion on the technology necessary to achieve unusually clean after-break edge quality.
If I need to "cut glass," why should I consider VPI?
Answer: Conventional scribing applications including windows, doors, table tops, etc., do not require the Precision Glass Scribing" technology developed by VPI. Conventional scribe placement accuracy and after-break dimensional tolerances simply do not require VPI techniques. If however, you require scribe placement relative to two targets (virtually all LCDs, most other Flat Panel Displays, and an increasing variety of thin or thick film products including sensors and solar cells), VPI technology is decidedly attractive. For other parts where the normal process is scribe, break, and grind, VPI technology typically reduces grinding requirements 25 - 75%. This savings alone often amounts to 25 - 50 % of your overall cost of manufacturing. (See "Why Buy VPI.") For further technical information, request VPI's "Precision Scribing of Shaped Parts" by Dr. Walter Scott.
Does the VPI equipment scribe with diamonds or wheels?
Answer: VPI utilizes both diamonds and wheels for scribing, depending on the thickness of the glass. Where glass thickness exceeds 0.25 mm (0.010 in.) VPI's Precision Glass Scribing technology delivers excellent results with one or more tungsten carbide cutting wheels in either linear or shapes products. Where glass thickness is less, diamonds are recommended. VPI has current customers scribing glass as thin as 0.050mm (0.002 in).
How long will one wheel last?
Answer: Wheel life depends upon many factors, including type of glass (soda lime or Borosilicate), thickness, size of substrate, configuration of the part, and the after-break edge quality required. VPI has customers that change wheels from once or twice per shift to once or twice per month, including two shift per day operations.
What about adge of chips?
Answer: VPI's SofStart allows the wheel to contact the glass at a speed significantly below normal scribe speed. First developed in 1975, this technique reduces "access" chips significantly. See also Factors Affecting Scribe and Break Yields in Flat Panel Display Manufacturing for further information on scribe quality.
How do I achieve superior after-break edge quality when my parts are scribed on your equipment?
Answer: The answer is to eliminate hooks, flares, and other unacceptable edge qualities normally experienced with scribe and break operations. See Factors Affecting Scribe and Break Yields for a contrast between conventional glass scribing and precision glass scribing. If the vent or crack is driven into the glass and the scribe substrate is "bent" less than one degree over a precise fulcrum, superior after-break edge qualities are normally experienced.
Will VPI scribeheads adjust to irregular surfaces on the glass?
Answer: All VPI scribers have a flotation system which allows a minimum adjustment of ± 0.250 mm (0.010 in.).
What sort of throughput yield can we expect after breaking?
Answer: VPI is constantly working with customers to increase their yield. After some study, most customers report a minimum yield of 98% and many are experiencing yields at 99% and above.
What is your maintenance record, specifically MTBF and MTBR?
Answer: Generally speaking, VPI customers do not want their competitors to know that they have VPI equipment due to the superior production capacity and higher anticipated yields. For this reason customer feedback on maintenance is extremely difficult to come by. Nevertheless, direct inquiries by VPI technicians have revealed that customers are typically maintaining 97 - 99 % fully available time.
What type of after-sale service can I expect in my country?
Answer: VPI thoroughly trains the staff of each and every customer upon delivery of the first machine. This training includes initial setup, turn on, programming, modifications to scribe programs, daily, weekly, and monthly maintenance routine, including preventive maintenance. Shortly after purchase, your buyer or designated engineer will begin to receive correspondence from VPI regarding shipment, installation, and training. Typically this requires 3-7 working days depending upon the machine. Twenty five years of experience confirms that once the customer understands his machine, down time and other operating difficulties are exceedingly rare. This service has proved so successful that VPI equipment will not be sold without installation and training.
What is VPI's market share in the world wide Flat Panel Display industry?
Answer: While the numbers change daily and the methods of calculations are inconsistent, the following numbers are approximate:
Total LCDs produced on planet earth: VPI - more than 50%
Total Flat Panel Display customers: VPI - 60 - 70%
Total square meters of glass: VPI - 30 - 40%
Please describe the laminate or "batch" scribe concept in terms of actual scribe.
Answer: VPI scribers induce a crack (vent) into the glass that causes an actual fissure to occur from 20-100% of the glass thickness. Because of precision glass scribing (PGS) technology, there is no "healing" of the scribe, and the after-break quality is considered "superior" by authorities in the field. Because of VPI's vent, LCD Panels or laminates (2 substrates sealed together) can be scribed and then broken. The after-break edge quality is superb even when the edge of a part on side one is not congruent to the same part on side two (pin-out).
Will VPI scribers effectively scribe materials other than glass?
Answer: VPI has been successful on Borosilicate, alkali-free alumino silicate, and soda lime glass in thickness ranging from 0.050mm (0.002 in.) up to 6.0mm (0.25 in) and tests are underway for glass thickness up to 10.0mm (0.40 in). In addition, the following materials have been successfully scribed with VPI equipment:
aluminum oxide,
aluminum nitride,
silicon carbide,
quartz,
fused quartz,
and lithium niobate.
VPI Research and Development is always available for scribing different materials. If you have a product where scribe and break technology is attractive to the on going process, please contact Villa Sales.
What is the maximum throughput of VPI Precision Glass Scribing Machines?
Answer: Maximum throughput varies greatly based on (1) the size & shape of the individual glass products and (2) the size of the motherglass. Please contact Sales and request an "Acquisition Justification Analysis" to determine the specific production volumes and machine-related costs of each of your company's product types.
Do you need to use cutting oil to ensure good scribe quality with VPI machines?
Answer: No. Exceptional edge qualities are always expected from VPI's "dry" scribing technique.
What is the tightest radius that the "Shapes" scribers can deliver?
Answer: One-eighth of an inch or 3.175mm.
What is the wheel to wheel holder ratio?
Answer: Depending upon the wheel, one wheel holder will remain in specification for five (5) to ten (10) wheel, axle, and bushing changes.
How do I send a board in for repair?
Answer: Simply, contact Customer Service by E-mail or phone at 602.266.2366, and request a Return Materials Authorization number. A brief description of the problem or symptoms will be helpful.
What is the lead time for a service or training visit?
Answer: Usually, a Service Engineer can be scheduled for a service or training trip within five (5) days of the request. If there is an emergency, a Service Engineer can normally be there within 24 hours.
What is the minimal order for wheels, axles, and bushings?
Answer: There is no minimal order, however, there are significant price breaks with bulk orders. It is recommended that a "blanket" order for one (1) year be placed to ensure availability and to take advantage of preferred pricing.