Forest Liné portal milling machine
Electrical and mechanical overhaul with modifications
Machining technology, fixture construction and special-purpose machine construction
A few years ago, the machine was converted to a Heidenhain iTNC530 with new motors and drives, while components such as hydraulics, lubrication and control cabinet were retained. The control unit and drive package in the control cabinet were renewed.
The contactors, transformers and relays for machine control as well as the wiring of the initiators were not removed for cost reasons, which however extended the commissioning of the machine by 3 to 4 weeks.
As a result, process reliability during tool change was no longer ensured, so that the tool changer was removed from the machine and programmed out of the control some time later. Without the tool changer, the machine could no longer be used flexibly in automatic mode.
The head lubrication only worked sporadically, so that the speed had to be reduced to 1,500 to 2,000 rpm to avoid overheating.
- delivery and installation of a new control cabinet, mounted on the mobile portal, at the rear of the Y-axis
- the power modules of the Siemens 611 series and the drive motors could be retained
- delivery and installation of a new tool changer, designed as a chain magazine, on the side of the machine. Standard tool diameter 120 mm, max. tool diameter with free adjacent positions 250 mm
- delivery and installation of a water-cooled main spindle motor (25 kW at 1,750 rpm.)
- delivery and installation of a new coolant system with paper band filter and frequency-controlled coolant pump with a capacity of approx. 1,700 l
- retrofitting kinematics OPT and measuring probe for automatic head calculation
- delivery and installation of a hydraulic unit with valve block and measuring motor for position indicator of the A-axis position
- delivery and installation of a new nitrogen accumulator for weight compensation, with safety block
- delivery and installation of a lubrication and cooling unit with monitoring for the angle head
- delivery and installation of a cooling unit (cooling water recooler), mounted on the portal for cooling of the control cabinet, main spindle motor and the angle head lubrication with flow monitor for monitoring the cooling effect in the head
- delivery and installation of a new Z-axis ball screw with bearing modification, new pulleys and HTD toothed belts
- delivery and installation of a new Y-axis ball screw with new motor mount, bearing, pulleys and toothed belt; change of the pitch of the spindle as a measure against swing-up
- overhaul and reworking of the angle head
- new bearing of the main spindle gear and replacement of the corrugated sleeve
- replacement of the trailing cable in all three axes and installation of the X-axis trailing on the hall wall at a height of approx. 3 m
- safety device on the travel portal in X direction with bumpers (safety foam edges)
- coolant change from internal to external cooling via pneumatic cylinder
- replay of the complete control software, reprogramming of the parameters (PLC)
The above overhaul of the machine has established a reliable machine condition and up-to-date machine safety. A cost-intensive purchase of a new machine could be avoided.