Cutting by Milling - Course: Techniques for Machining of Material. Instruction Examples for Practical Vocational Training: Instruction example 6.1.: Backing material

Cutting by Milling - Course: Techniques for Machining of Material. Instruction Examples for Practical Vocational Training

		(introduction...)
		Introduction
		Instruction example 6.1.: Backing material
		Instruction example 6.2.: Measuring point
		Instruction example 6.3.: Fixing bush
		Instruction example 6.4.: Segment

Instruction example 6.1.: Backing material

A cuboid-shaped bar stock (bar steel) with a length of 850 mm has to be cut by means of a metal slitting saw blade into several one-off parts by cutting by milling.

Material

St 38 (structural steel, tensile strength 380 - 500 MPa)

Figure

Dimensions

40 x 40 x 80 mm (finishing sizes)

Milling machine

Horizontal milling machine

Tools

Metal slitting saw blade (Ø 180 - 200 mm x 2.5 - 3 mm), cutter arbor (long), machine vice, lock screws, keys, flat file

Measuring and testing means

Vernier caliper, bevelled edge square, dial gauge, steel square

Auxiliaries

Separating jaws for a machine vice, stop bar for the separating jaws, chip brush, hand broom, cleaning rag, T-slot cleaner, tongues for the machine vice

Required previous knowledge

To read a drawing, to measure and to test, to set-up and to operate horizontal and vertical milling machines, to mill front surfaces

Explanations to the working drawing

0,10

The maximum deviation from angularity is 0.10 mm

Sequence of operations	Remarks

1. Batch-quantity (number of the bars) and length control (size 850 mm)	Comparison with the specifications of the work accompanying data sheets

2. Functional test and lubrication of the milling machine	Lubrication and oil-level check according to the lubrication schedule

3. Fixing and adjusting the machine vice (along the machine table)	Adjustment, localization by means of tongues and steel squares

4. Placing the separating jaws into the machine vice	Separating jaw should always be used batchwise (in pairs).

5. Fixing the cutter arbor and fasten the metal slitting saw blade	Do not forget the feather key! Place the end support as near as possible to the metal slitting saw blade.

6. Setting-up the coolant and the milling safety systems

7. Clamping in the workpiece (bar stock) after having fixed the length feed stop	The length feed stop results from fixing a parallel part/strip into the premanufactured slots of the clamping jaws.

8. Fixing the cutting values	The values should be taken from the nomogram or a table.

9. Position the milling table into working position	Mechanically with the rapid traverse or with manual adjustment (X-Y-Z-direction).

10. Start cutting with the rotating metal slitting saw blade by manual adjustment of the milling table	The length size (80 mm) should be fixed as precise as possible according to the marking on the workpiece and after the first cut correspondingly corrected.

11. Cutting by milling of the first workpiece after a possible correction of the length size	Observation of the cutting process is necessary! At a "standstill" of the metal slitting saw blade switch off the machine immediately! Take back the milling table manually and clamp the metal slitting saw blade tighter by "fastening" the arbor nut.

12. Declamp, deburr and clean the workpiece, make a quality control.	Control of the dimensional accuracy, parallelism and surface finish

13. Going on with the cutting by milling at a permanent control of the quality requirements	In case of an impaired surface finish you have to change the metal slitting saw blade!

Backing material