WV090 PEEL AND PULL OFF TEST MACHINE Issue: B 27/10/04

Transcription

1 WV090 PEEL AND PULL OFF TEST MACHINE Issue: B 27/10/04

2 090_b.doc INDEX 1. INTRODUCTION TO THE TESTS 1 PAGE 2. DESCRIPTION OF THE EQUIPMENT 2 3. INSTALLATION 4 4. OPERATING INSTRUCTIONS 5 5. TEST RESULTS MAINTENANCE MACHINE SPECIFICATION STANDARDS TEST EQUIPMENT DRAWINGS 18

3 1090_b.doc Page 1 1. INTRODUCTION TO THE TESTS The Peel and Pull Off test machine is produced to perform tests on printed circuit boards, however it has a number of other applications such as the peel strength of labels and adhesive tapes, pulling off wire terminations, insertion forces of plugs and sockets, pulling wire wrapped terminals checking fabric strengths etc, etc. The machine has been designed to conform to the British Standard 9760 part for peel strengths of conductors, and part covering pull off strengths of pads on single sided and double sided boards and, with the optional Peel Wheel, part enabling the peel strength of conductors of flexible circuits to be measured. The machine will accept the standard test coupon or can handle finished panels which may require testing.

4 2090_b.doc Page 2 2. DESCRIPTION OF THE EQUIPMENT The Peel and Pull Off test machine consists of a base frame upon which is mounted a substantial aluminium casting. The vertical motion is achieved by means of a stepper motor, driving through a reduction gear to the lead screw, a block on this screw drives a shaft, running in recirculating ball bushings, which carries the load cell. A second, smaller, stepper motor is fitted with a gear which engages with a rack attached to the horizontal table assembly, again running on recirculating ball bushings. The mechanical assembly is housed within a glass reinforced plastic moulding, through which the load cell and table protrude, the load cell is fitted with a wire clamp to hold the samples wire whilst the table has a beam which clamps either complete panels or, using the insert plate, standard test samples. Mounted within the moulding is a power supply unit with the mains switch, plugs and sockets for the mains input, the printer supply and pen graph recorder. The computer module is fitted into the moulding and houses the microprocessor, the keypad and the liquid crystal display. A ribbon cable links the computer to the power supply. The control of the stepper motors are made via the keypad and the output from the load cell is shown on the display. The unit allows a choice of units to be selected, Newtons, Kilogrammes and Pounds, and features a facility to change the range of units by a factor of 10 to cover either the Peel or Pull test. A direct reading of the force is shown on the display and a maximum force is displayed for Pull off tests. The Peel test also gives a display of maximum force but a more useful minimum force can also be called up.

5 3090_b.doc Page 3 The optional printer takes the results of the test (be it Peel or Pull) and gives a graphic copy of the test along with maximum and minimum forces where applicable. Also on the print out is the time that the test ran for. A graphic copy may also be achieved by connecting a pen graph recorder to the jack socket provided. For measuring the Peel strengths of flexible circuits an optional Peel Wheel assembly is available which replaces the standard beam and enables tests to be carried out in accordance with B.S part

6 4090_b.doc Page 4 3. INSTALLATION The equipment should be sited on a firm level base in a clean dust free environment. Connect the machine, using the mains lead provided, to a suitable 220/240 volt single phase socket. (The machine can be supplied for other voltages on request).

7 5090_b.doc Page 5 4. OPERATING INSTRUCTIONS If fitted, connect the printer and switch on both the machine and the printer. SET DATE: eg. 08/02/89 If a printer is connected enter the date using the keypad, note that the oblique is entered using the ZERO (Z) key as no decimal point is provided. If no printer is fitted or being used just press ENTER (E) to bypass that instruction. 0 SET FORCE UNITS 1 SET FORCE RANGE 2 REPRINT/DISP 3 SET SPEED Set the units of force, press key 0, Select unit of force 0 LBS 1 KILOS 2 NEWTONS Choose the desired unit in which the tests will be carried out, eg. For Newtons press key 2.

8 6090_b.doc Page 6 The display reverts back to the main menu. Note: if no units of force are selected the machine will automatically default to Newtons. Prepare the samples as specified in the relevant test procedure, note that for the Peel test and track should be peeled from the base laminate before soldering the wire. For both tests a hard drawn brass wire, approximately (1.25mm) diameter should be used. PULL TEST The machine needs to be set to the higher force range for a Pull test, therefore select the force range. 0 SET FORCE UNITS 1 SET FORCE RANGE 2 REPRINT/DISP 3 SET SPEED Press key 1, RANGE IS 25N 0 CHANGE RANGE Press key 0, this will change the force range from 25 to 250 and back again. Select the higher range, ie. 250 newtons. If working in pounds the ranges are 5 and 50 lbs and and for kilos the ranges are 2.5 and 25 kgs. Note: the ranges stated are approximate and may vary slightly either way.

9 7090_b.doc Page 7 6. Press the MENU (M) key, 0 SET FORCE UNITS 1 SET FORCE RANGE 2 REPRINT/DISP 3 SET SPEED Set the test speed, for a pull test no specific speed is defined in the BS specification but a load rate of no greater than 50 N/sec is required. A little experimentation may be called for to achieve an ideal speed, but a good starting point is 25 mm/min. To set the speed press key 3, INPUT SPEED mm/min Old=50? Key in the speed required, eg. 25 and enter the value using the (E) key. The maximum speed is 75mm/min, speeds above this value will not be accepted. The display reverts to the main menu again, press the MENU (M) key to move on to the test start condition. Please wait This display shows for a short time only whilst the load cell Tares or zeros, now, FORCE MAXF table 0 0N OFF range 2 Start test 250N

10 8090_b.doc Page 8 This start menu shows a number of conditions of the state of the machine, eg. The actual and maximum forces exerted by the load cell The state of the drive to the table, ie. On or off The range which has been selected If the FORCE does not read 0 press the ZERO (Z) key to tare the load cell. Load the sample by clamping it to the table and inserting the wire in the gripper. Use the UP (1) or DOWN (0) keys to raise or lower the gripper to a convenient height. To move the table to the left or right, use the (7) or (8) keys. Note that there are limit switches at the ends of the travel in both directions. To start the test press (2), the load cell will be driven up at the predetermined speed. As the sample is pulled the force can be observed on the display, this force will be the same on both readings whilst the load increases. When the sample fails the FORCE will return to zero whilst the maximum (MAXF) will be held and displayed. If the maximum force that the load cell can exert (250 if using the Newton units) is exceeded then the test sample will be deemed to have passed and the test curtailed. Whilst the test is in operation FORCE MAXF table N OFF 28s range 0 Stop & down250n When the test is complete ie. either the pad is pulled out or the maximum force exceeded, the vertical drive can be stopped using the STOP (S) key. Alternatively the load cell can be returned to the bottom of its travel by pressing the Stop and down key (0). Use the Stop (S) key to stop the motion at any point. Once the STOP or STOP & DOWN keys are pressed. Results of last test 0 Print them 1 Display them

11 9090_b.doc Page 9 This display can also be produced if on the main menu, key (2) REPRINT/DISP is pressed to give this display. If a printer is connected pressing key (o) will initiate the printer to give a graphic copy of the results of the last test. While the printer is in operation no commands are accepted by the computer and the Busy printing Note: If the test exceeds 100 seconds only the last 100 seconds will be printed. When the print out is complete the display reverts to the start menu. If no printer is connected the computer recognises this and sounds a buzzer whilst the Enable printer! After a short period the display reverts to the results menu. The maximum force can be displayed if the (1) key is pressed. It will be noted that the display will not show the minimum force as this is irrelevant for a Pull test. Press the MENU (M) key to call up the Start menu, or press (M) again to call up the main menu.

12 10090_b.doc Page 10 PEEL TEST To perform a PEEL test on a rigid specimen the instructions should be followed as described, for tests carried out on flexible specimens using the optional PEEL WHEEL (or German wheel) the table will not be driven during the test therefore please read the note at the end of this section to ensure the minimum force reading is displayed. For PEEL tests the lower of the two ranges is required, ensure the main menu is selected, if not press MENU (M), 0 SET FORCE UNITS 1 SET FORCE RANGE 2 REPRINT/DISP 3 SET SPEED Press key (1) RANGE IS 250N 0 CHANGE RANGE To change the range, press (0) RANGE IS 25N 0 CHANGE RANGE Press the MENU (M) key to call back the main menu, 0 SET FORCE UNITS 1 SET FORCE RANGE 2 REPRINT/DISP 3 SET SPEED

13 11090_b.doc Page 11 Set the test speed for the PEEL test, if working to the BS spec this is 50mm/min, therefore press (3), INPUT SPEED mm/min Old = 25? Enter the speed required, eg. 50 and enter with the (E) key. This display returns to the main menu, press (M) to call up the Start menu. Tare as before it FORCE is not zero by using the ZERO (Z) key. Note: that in the low range the load cell is reading microvolts to measure these small forces and consequently will be affected by heavy movement nearby or even blowing on the top of the load cell. FOR TESTS ON RIGID MATERIAL:- Slide the sample under the clamp plate with the brass wire at the right hand end of the plate, use the table left and right keys, (7) and (8) to move the table so that the end of the tract is directly beneath the wire gripper. Use the up and down keys (1) and (0) to move the gripper vertically to enable the wire to be inserted into the gripper. Clamp the wire in the gripper. Ensure that the length of the wire is such that the gripper is near its lowest position. (Otherwise there may be insufficient travel to complete the test within the limits of the specification). To start the test press key (2). As the track starts to peel away from the base laminate press TABLE (T), the display will record the fact that the table has been engaged (shown as (ON) the table will now be driven, maintaining a 90º pull. Ensure that the track does not become detached at the end of the test, either the machine will stop at the end of its travel or it will be necessary to press either STOP (S) or the Stop and down command (0) is pressed both the vertical and horizontal movements will return to their start positions. The display will be reading the actual and the maximum force during the test. When the test has been stopped the Results of last test 0 Print them 1 Display them

14 12090_b.doc Page 12 As with the Pull test choose how the results are to be indicated by selecting (0) or (1). It will be noted that when displayed, the minimum force, which is more relevant in the Peel test, is given on the display. Once the print-out is completed the machine can be reset for the next test. The printed results will show a graphic copy of the test, the type of test being carried out, the minimum and maximum forces, the test speed and the date. FOR TESTS ON FLEXIBLE MATERIAL:- Using a sample cut to a suitable length, lift the tensioning bars out of their slots and wrap the material around the wheel with the free ends at the clamp, this may be done with the wheel in place or removed from the holder, whichever is most convenient. Slacken the clamp and tuck the free ends of the material under the clamp, tighten the clamp and slip the tensioning bars into their slots to pull the material taught. Attached one end of the track, after peeling a little from the base material, to a piece of brass wire and insert the wire into the grip as with the rigid test. As the track starts to peel press the TABLE key twice in quick succession, (the display will first show ON and then OFF ) this will tell the computer that it is performing a PEEL test and it will, therefore, provide both maximum and minimum forces. The action of momentarily engaging the table will not effect the results. Continue as with the instructions for rigid materials.

15 13090_b.doc Page 13 5 TEST RESULTS The minimum Peel and Pull Off forces for the relevant test samples are given in the B.S to 9766 and these values may be compared to the actual values recorded (either on the display or the print out). Generally low readings or test failures may well be attributable to poor, laminate supplies. Random low readings or failures could be poor laminate with an uneven bond strength throughout the panel or, alternatively the processing may be effecting the sample. Experience has shown that in general the bond between the base laminate and the copper are usually well above the minimum forces laid down in the relevant standards. As tracks become narrower it is important that a good bond exists between the copper and the laminate, therefore tests on actual sample boards allow real Peel strengths to be measured the minimum forces are quoted per unit width, therefore the actual force can be calculated pro-rata.

16 14090_b.doc Page 14 6 MAINTENANCE Always disconnect the machine from the mains before carrying out any servicing operations. The machine has been built such that a minimum of maintenance is necessary to keep the unit in working order. The cabinet may be cleaned with M.E.K. or a similar cleaner if dirty, and polished with any domestic wax polish. Scratches or other such marks may be removed by carefully polishing with a fine cutting compound and then waxing. Every three months lay the machine on its back, ensuring that some suitable protection is laid on the bench first, and clean the shafts which support the table and the vertical shaft. Lightly oil these shafts. Lubricate the lead screw with a molybdenum based grease. The gearbox is sealed for life and require no attention. All other bearings and gears require no lubrication and should be left dry. The load cell is checked and calibrated when new, if required the unit can be checked annually on site or by returning it to the manufacturers for calibration using hang weights which are traceable to national standards.

17 15090_b.doc Page 15 7 MACHINE SPECIFICATION Vertical travel : 100mm typ. Horizontal travel : 100mm typ. Speed : 0 75mm/min. Low range reading : 0 25 N typ. High range reading : N typ. Power consumption : 200 watt Voltage : 220/240 (or to special order) Dimensions (mm) : 675W x 590D x 550H Weight : 25 Kgs

18 16090_b.doc Page 16 8 STANDARDS The machine has been manufactured primarily to cover the BS 9760 tests for Peel and Pull Off, however this specification is closely related to a number of standards used throughout the world and the machine can be used to carry out tests to most standards, examples of such tests are as follows:- BS Pull off Lands with plain holes BS Pull off Landless plated through holes BS Peel Rigid panels BS Peel Flexibles. (Adapter required) BS Peel After immersion in solvent BS Appendix C Peel BS Appendix D Pull BS Peel Standard conditions BS Peel Elevated temperatures. (Adapter reqd). BS Peel Flexible circuits. (Adapter required). BS Pull off Lands with plain holes BS Pull off Landless plated through holes IEC Peel Standard conditions IEC Peel Elevated temperatures. (Adapter reqd) IEC Peel Flexible circuits. (Adapter required) IEC Pull off Lands with plain holes IEC Pull off Landless plated through holes

19 17090_b.doc Page 17 9 TEST EQUIPMENT The following equipment is available to compliment the equipment referred to in this handbook. This equipment is designed and produced to meet the BS 9760 requirement, however it is suitable for any company wishing to test and inspect a variety of printed circuit boards, either for internal use or to a customers standards. Please contact CEMCO for further information on any of these products. CEMCO No. DESCRIPTION USED WITH 83 TEMPERATURE CONTROL UNIT CEMCO CHANGE IN RESISTANCE ANALYSER 85 PRINTER CEMCO 89, 90 & PEEL WHEEL CEMCO MULTI FUNCTION SOLDERABILITY UNIT (ROTARY, DIP & GLOBULE TESTS) 90 PEEL AND PULL OFF 91 ACCELERATED AGEING 92 PLATING ADHESION ROLLER 93 SOLVENT RESISTANCE 94 FLEXURAL FATIGUE 95 ROTARY SOLDERABILITY 98 SAND BATH/WATER BATH CEMCO FILM AREA MEASUREMENT

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