A rotary milling SPM used to mill ingates was developed for a foundry based company as a solution for the following problem:

• Inagates of castings had to be removed before machining on VTLs.
• They were previously being removed by hand grinding.
• This was a laborious process requiring a lot of man power.
• There was a lot of dust, which was hazardous and of no use.

Key points of the solution offered:

• The ingates are milling within minutes compared to the previous numerous man hours spent to hand grinding.
• Better tool life of the final machining as ingates are removed uniformly.
• Milling chips are generated which can be used again in castings. Earlier these becoming powdered chips which could not be collected or used.

Features and Specs:

• Rigid, heavily ribbed, stress relieved, cast iron structure for slides. Fabricated structure for base.
• Atop the base, a vertical column is mounted with vertical slide.
• Both the slides are made of LM guides and blocks.
• Atop the slide, a 5 HP all geared milling head is mounted.
• The cross slide is driven by ballscrewscrew, coupled to inline servo reducer and servo motor.
• The machine also has a rotary table mounted in front. The drive is motorized and routed through servo motor with variation between 0-15 RPM

 

Technical Specification:

Machining Capabilities
Milling Capacity in Steel (max)	Ø63mm cutter x 10 mm depth of cut
Y axis – Vertical Slide
Stroke	300 mm
Guideway details	All cast iron sliding surface.
Slide drive	Screw rod and phosphorus bronze nut
Drive	Hand Driven (Manual) through wheel
Bellow cover protection	Collapsible bellows
Lubrication system for axes	Centralized lubrication system integrated with PLC
Slide end stop limit switch arrangement	Will provide feed end limit switches.
Wipers for slide	will be provided
Z axis – Cross/Ram slide
Stroke	300 mm
Guideway details	Both male & female sliding surfaces are all-cast iron
Traverse rate	1000 mm/min
Ram size	minimum 150 square
Slide drive	rolled ballscrew coupled to servo motor through inline servo reducer
Servo motor rating	2.4Nm, 0.5kW
Servo reducer ratio	01:10
Auto Feed / Manual Feed Selection	Will be provided
Lubrication system for axes	Centralized lubrication system integrated with PLC
Slide end stop limit switch arrangement	Will provide feed end limit
Wipers for slide	will be provided
Spindle Head & Spindle drive
Tool clamping taper of spindle	ISO-40
Tool Locking system	Automatic Arbour clamping through disc spring stack and hydro-pneumatic cylinder
Capacity of tool holder (weight / size)	max Ø160 mm cutter
Spindle Bearing configuration	Match pair angular contact bearings
Lubrication system of head	Molybdenum Sulfide Grease packing for life (ISOFELX NBU 15 of Kluber make)
Spindle speeds	Stepped spindle speed of 200,360, 500 & 960 RPM as standard. Or 100-1600 RPM with VFD interface (Optional)
Spindle speed range selection	VFD interfaced(Optional) motor in combination with lever operated change gear
Lubrication of spindle drive gearbox	Recirculating oil bath
Main Spindle motor rating	5HP
Other Equipment
Rotary table speed and indexing	0 Al 15 RPM and indexing of 275°
Rotary table drive	Servo driven
Operators control station	Will be provided
Electrical Panel	Will be provided
Major bought-outs
AC motors	KEC/ABB
Servo Motor, PLC and HMI	Mitsubishi
Limit Switches	Teknic, Siemens
Major Switchgear elements	Schneider/ Siemens
Cables	Finolex

SEQUENCE OF OPERATION:

• Load the first component.
• Adjust the milling head height with respect to the ingate pad height and milling cutter.
• Adjust the cutter depth.
• Press auto-cycle.
• The component gets clamped.
• The ram head moves to the milling depth.
• The rotary table rotates at feed to mill the first ingate.
• The rotary table indexes by 180° in rapid.
• The rotary table rotates in feed to mill the second ingate.
• The rotary table rotates back to home position in rapid.

Video of Working: