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TEST TABLES Vibco’s test tables result in savings on manufacturing costs, increased product reliability and greater customer confidence by detecting future failures right in your own plant, prior to shipment. Defective electrical components and connections fail under the induced vibration, helping you to quickly identify the problems. This eliminates embarrassing and costly repair and difficult tracing of circuits in the field. The simulation of transportation and handiing shocks, on the Vibco test tabie give the added advantage of showing up the defective solder loints, marginal connections and faulty components. Forces generated will not, however, effect components of sound integrity. The vibration also removes potentially harmful residue such as pigtail clippings. solder splashes and other debris lodged in the chasis. Vibco’s test tables are also extensively used in fatigue testing of many, varied electronic and space industry products, including: radios, TVs, military hardware, ights, computers, etc. LIVE TABLE TOP Exclusive Vibco design assures fuil and even vibration in all areas of the tabie top, guaranteeing the desired frequency and amplitude in every sc~uare inch. This enables the quality control station to utilize the full potential of the available working area. Quality Control can now standardize test procedures now that the consistency of testing and reliability of results is assured. Vibco's wide choice of variable frequency ans constant frequency equipment gives you the ultimate in low cost product liability testing. |
 Same a US-SA but with inflatable air mount vibration isolators, giving you additional amplitude control and adjustment for varying loads. Vibration isolation is lOO%. MODEL US—SA,(21" x 24" x 36" high) This is the most inexpensive test table available. Consists of: VIBCO’s popular US—900 high frequency (9,000 vpm) vibrator with speed adjuster and foot on-off switch. Rubber shocks between "Live Top" deck and stand isolate up to 97% of vibration from legs. |
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Most US SA or US-RD tables are used for verifying integrity of electric
circuits, simulating handling and transportation shocks, detecting
marginal connections, and removing residue. The vibration time varies
from part to part, from a few seconds of vibration to a minute or so. VlBCO’s test tables result in savings on manufacturing costs increased product reliability and greater customer confidence by detecting future failures right in your own plant, prior to shipment. Defective electrical components and connections fail under the induced vibration helping you to quickly identify the problems. This eliminates embarressind and costly repair and difficult tracing of circuits in the field. The simulation of transportation and handling shocks on the VIBCO test table give the added advantage of showing marginal connections and faulty components. Forces generated will not, however, affect components of sound integrity. The vibration also removes potentially harmful residue such as pigtail clippings, solder splashes and other debris lodged in the chasis VIDCO’s test tables are also extensively used in fatigue testing for many varied electronic and space industry products, including radios TV’s, military hardware, lights, computers, etc. Depending on the item, over -the-road transport testing is mostly done at 30 htz and at 2.2 to 5 g. We have built several test tables for testing aparatus for the government and Armed Forces when request has been 2.s g. Equipment for automobiles, batteries, etc., are normally tested at 5 g, 30 htz for 2 hours. Setting up a test program for a particular item for over-the-road transport is normally donr as follows. When desired "g" force has been decided, 2.2 g or 5 g, and the test equipment is theoretically set up to deliver this "g" force, put test model on the table and start the test. Check the model ever five minutes until the first part of it breaks. Replace the broken part and continue test until the next part breaks, repeating this process until most or all parts are broken. By replacing the broken parts as testing continues, you will get a good idea of the variance in quality of this item or if these items break after the same test time , you have to either live with this failure, get another make, or redesign, etc. By completing a destruction test on one unit, you will not only get to know which pieces are breaking and in which sequence, but also which ones and how many of these items to keep in field service or maintenance stock. You can, by vibration testing, estimate the time the unit will be in the field before maintenance is necessary. You can also design the unit to last a predetermined length of time. For example, if you have several units in the field and found that one piece breaks in three months you can go back to your destruction test and find out how long this item lasted in your test. If it broke in one hour of testing, you can relate one hour of testing equals three months in the field. If you want the unit to hold up for one year, the unit then must hold up for four hours of testing. When you have changed the marginal parts for better ones, different makes, redesigned the unit, etc., and it holds up for four hours of testing, you can then be reasonably certain it will last for at least one year in the field. The table Fixtures, be drilled bol ts when received is ready to plug into your power supply. straps, etc., can be attached to the table top. Holes can and tapped into it for this purpose. DO NOT secure these etc., to the bottom plate. Amplitude, G-value, and frequency can simply be determined by the following diagram. Simple amplitude meters can be made following either of the two designs below. Stick the amplitude drawing to thr item to be measured. Ehen the vibrator is started, the top and bottom line in the diagram will cross at one point. This indicates the amplituse in inches.  The formula for amplitude is listed below. VIBRATION FATIGUE TESTING The folowing standard terms are used in vibration fatigue testing. 1. Frequency (f) which is measured in cycles per secind or vibrations per second. 2. Amplitude (r), or deflection, is the radius from the axis of rotation to the outmost point the particle travels. 3. Displacement (d), or excursion or stroke, which is double the amplitude. 4. Accelration (a). In almost all fatigue testing the acceleration is expressed in relation to the acceleration due to gravity or in "g's" which is 32.174 feet per second, 386.1 inches per second. 5. Angular velocity (w), or radians per second. 6.Rotations per minute (n). 7. Force (p) in pounds. Click to enlarge  Click to enlarge  Consequently, to accelerate a weight with 2 weight is necessary; 3 g’s, a force three t and so on. Let us take an example: We want to vibrate 51 lbs. at 2 g and what ampi itude do we get. From formula (2) we get p = 51 x 2 p= 102 lbs. We get the amplitude from formula (1), 2= 2.83 x 10-5, (3000)2 r = .0078" The following chart gives the Volt—Frequency—Impact values for Model US-450, US—900, US-1600 and SCR—l000. NOTE: The chart is for an unloaded vibrator; the values will vary with the loads. We suggest you make up your own charts for your different loads and vibrators. This is easily done by the help of a rheostat and a frequency meter or a stroboscrope or a vibration pickup. We have a component weighing 16 lbs. which we want to test at Sg acceleration. What force is needed and what ampi itude do we get. We now must bring the weight of the table top and the vibrator into our calculations. Since the table top is 8 lbs. and the vibrator (US—450) is 16 lbs., the total weight is 24 lbs. We use formula (2). 4O x 5 200 lbs. A 200 lb. centrifugal force or impact is needed. We now refer to the chart and find that the frequency for a 200 lb. force is 6000 rpm, which is gotten by adjusting the rheostat to 80 volt. To select the best vibrator for your needs, calculate as follows. Note: Always use maximum values, since you can always go lower with frequencies and impacts. You know at what maximum g's you want your parts or components tested. Let us say the maximum is 10 g’s, and the maximum weight of the part to be tested is 20 lbs. Estimate the table top (usually 1/4 — 3/8” plate is used) at 9 1bs., and the vibrators weight (let us try Model us-L,50) is 16 lbs. The total weight of part to be tested, the table top, and the vibrator is then 45 lbs. Use formula (2). 45 x 10 = 450 lbs. centrifugal force or impact is needed. We then select Model US-450, which will give 450 lbs. impact at 7500 rpm. If you need any further information, assistance or help feel free to contact our Engineering Department at any time. There is no charge or obligation for this service.  Please click for a larger image    |
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75 STILSON RD, P.O. Box 8 WYOMING, RI 02898 Phone: (401) 539-2392 (800) 633-0032 Fax: (401) 539-2584 E-Mail:vibrators@vibco.com |