 | Cutting by Milling - Course: Techniques for Machining of Material. Instruction Examples for Practical Vocational Training |
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Instruction example 6.2.: Measuring point
A strip shaped bar stock at a length of 550 mm has to be cut with a metal slitting saw blade into one-off parts by cutting by milling.
Material
St 60 (structural steel, tensile strength 600 - 750 MPa)
Figure
Dimensions
20 x 24 x 50 mm (finishing sizes)
Milling machine
Horizontal milling machine
Tools
End face mill (Ø 100 mm), metal slitting saw blade (Ø 125 - 160 mm x 2.5 - 3 mm), cutter arbors (short and long), machine vice, chucking screws, flat file, keys
Measuring and testing means
Vernier caliper, bevelled edge square, steel square
Auxiliaries
Separating jaws for the machine vice, stop bar for the separating jaws, chip brush, hand broom, cleaning rag, T-slot cleaner, tongues for the machine vies
Required previous knowledge
To read a drawing, to measure and to test, to set-up and to operate horizontal and vertical milling machines, face milling
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Sequence of operations |
Remarks |
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1. Batch-quantity (number of the bars) and length control |
Comparison with the specifications of the work accompanying data sheets |
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2. Functional test and lubrication of the milling machine |
Lubrication and oil-level check according to the lubrication schedule |
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3. Fixing and adjusting the machine vice (along the machine table) |
Adjustment, localization by means of tongues and steel square |
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4. Clamping in the cutter arbor (short) and fastening of an end face mill (about Ø 100 mm) |
The short arbor and the end face mill are provided for face milling of one side of the bar stock. |
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5. Setting-up the coolant and the milling protective systems |
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6. Clamping in the bar stock in multi-piece clamping (2-4 bars) |
The workpieces should be clamped in so that they stand out from the vice only short. |
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7. Fixing the cutting values for face milling |
The values should be taken from the nomogram or a table. |
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8. Position the milling table into working position |
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9. Scratch marking at rotating mill and "clean milling" of the end faces |
"To mill clean" does mean that the cut is as low as possible. |
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10. Declamp the workpieces, deburr, clean and control of the angularity and surface finish |
Use proper files only - otherwise there is an injury hazard! |
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11. Changing the cutter arbor and the milling tool - fixing the coolant and the milling protective systems |
Clamping in the cutter arbor (long) and fastening the metal slitting saw blade. |
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12. Placing the separating jaws into the machine vice |
Separating jaws should only be used batchwise. |
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13. Clamping in two bars for cutting by milling after having fixed a length feed stop |
When clamping in the work-pieces, they should be arranged with the milled end face to the length feed stop. |
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14. Fixing the cutting values for cutting by milling |
The values should be taken from the nomogram or a table. |
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15. Position the milling table into the working position |
To be positioned into the X-Y-Z-direction |
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16. Start cutting with the rotating metal slitting saw blade by manual adjustment of the milling table |
Make a dimensional inspection and a possible correction after having started cutting (length size 50 mm). |
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17. Cutting by milling of the first workpiece after a possible correction of the length size |
The rotating metal slitting saw blade should be observed permanently and in case of disturbances (e.g. "standstill") the machine should be switched off. |
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18. Declamp, deburr, and clean the workpiece and do a quality control. |
Control of the dimensional accuracy angularity, parallelism and surface finish |
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19. Continuation of the cutting by milling at a permanent control of the quality requirements |
With a large number of pieces a timely changing of the metal slitting saw blade is recommended. |
Measuring point
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