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Deep Rolling and Roll Straightening Machines

HEGENSCHEIDT 7625 - Flexible machining of large crankshafts up to 4000mm length

In powertrain applications, deep rolling is an attractive manufacturing technology for improving the operational stability of highly stressed crankshafts for automotive, commercial vehicle and industrial engines. The deep rolling process induces compressive residual stresses into the bearing fillets of crankshafts. HEGENSCHEIDT has had a decisive influence on this technology and has developed special machines for the economical machining of crankshafts with its deep rolling and  roll straightening machines.

Areas of use and application

 

The 7625 is a HEGENSCHEIDT deep rolling and  roll straightening machine for machining large crankshafts up to 4000 mm in length, for example for emergency power generators, marine or diesel engines as well as construction machinery and commercial vehicles. The special machine, which is designed to tto the requirements of the market, provides an economical, energy- and resource-saving process for increasing the fatigue strength of crankshafts and minimising the radial run-out of main bearings. 

Deep rolling of main and pin bearing fillet radii and roll straightening of main bearings can follow directly after the pre-machining turning operations of main bearings and milling of pin bearings in order to increase the fatigue strength of the large crankshaft and to correct possible main bearing run outs. By roll straightening the pre-machining cost can be reduced significantly by less stock allowance and semi-finishing machining cost for grinding can be reduced as well by less grinding tool cost due to low TIR run-outs. Type 7625 was designed as a stand-alone machine to meet all the requirements of highly flexible crankshaft production with varying quantities and geometry of bearings.

 

Added value

Economic advantages

  • Energy saving process
  • Low production and manufacturing cost
  • High production rate
  • Low maintenance cost
  • High machine availability
  • Less stock allowance (pre-machining)
  • Less grinding material (semi-machining)

Flexible machining concept

  • High flexibility for part families with varying stroke, journal spacing & journal quantity
  • Automatic stroke adjustment
  • Quick change-over from one family type crankshaft to another
  • Direct loading into machining position and low loading height
  • Automatic radial positioning
  • Integrated laser measuring probe to check stroke and angular position
  • Angle dependent rolling for minimized run-out and reduced shoulder deformation
  • Measuring of the total indicated run-out on all main bearings
  • Measuring of run-out with reference to centers or to vee-blocks
  • Straightening of crankshafts without loss of fatigue strength
  • Roll straightening computer with software for all common types of crankshafts
  • Self teaching roll straightening program
  • High degree of process capability by monitoring all parameters
  • Monitoring of fillet penetration depth
  • Tool monitoring system
  • Tool design for long tool life

Function

Our innovative machine model 7625 combines the deep rolling and roll straightening technology to improve both, the fatigue strength of crankshafts, and the radial run-out of the crankshaft main bearings. Combining these two features in one machine enhances product quality, process capability, and improves process efficiency.  After the crankshaft has been loaded, pre-centered, and fixed by using a compensating chuck, the integrated NC-operated spindle positioning system gages the radial position and stroke of the crankshaft and rotates the crankshaft into the correct deep rolling position. The deep rolling units with durable tools automatically encircle the crankshaft main and pin bearings. The fillet radii of these journals are then deep rolled with angle dependent rolling force control. Precision probes measure the TIR at the main bearings. The measured values are relayed to the roll straightening program for evaluation and precise identification of the direction and degree of radial run-out. This data is the basis for the roll straightening process to reduce the run-out. The incorporated process management system monitors the penetration depth within the radii for optimum process reliability.

Highlights of the 7625  

Machine specification

Machine data
Machine dimensions (L x W x H) 12,000 mm x 3,600 mm x 3,000 mm
Machine dimensions incl. maintenance area (L x W x H) 15,000mm x 6,000 mm x 3300mm
Centre machining axis above floor level 1,285mm
Machine weight (incl. equipment) ~ 35 t
Operating voltage 3 x 400V AC, 50Hz
Control voltage 230V AC, 50Hz
Solenoid valve voltage 24V DC
Connected load ~ 66 kVA
Working temperature (standard) 10 ... 40 °C
General specification
Number of deep rolling units, max. 2
Number of deep rolling tools, max. 4
Deep rolling force, max. (type 7625-140kN) 140kN
Hydraulic pressure 140 bar
Tank capacity hydraulic oil unit 160 l
Tank capacity rolling oil centrifuge type filtration system 315 l
Coolant hydraulic 20 l/min
Workpiece data  
Weight, max. 1 t
Length 850 ... 4.000mm
Diameter flange, max.

90 ... 270 mm

Diameter main and pin bearing 90 ... 220mm
Width main and pin bearing 40 ... 230mm
Stroke adjustment up to 220mm
Diameter of counterweight, max. 450mm
Crank angle all

 

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Brochure

Here you will find all the contents of 7625 as a download.

DOWNLOAD | PDF 0.40 MB

Our Services

We adhere to the principles of competence, speed, and professionalism in order to provide you with the best possible support for your daily work. As a reliable and globally positioned partner, we support your company and your machine throughout their entire life cycle. We are committed to ensuring your productivity, coupled with the fastest response times and maximum machine availability. This is why HEGENSCHEIDT machines and services are perfectly matched. We provide uncomplicated and fast support for necessary repairs, replacement parts, services, or technical questions. Our range of services and support at the highest technical level is clearly structured and comprehensive.

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