• Excavator

Hydraulic valve housing

Everything depends on the main bore. Manufacturing valve housings is the supreme discipline in the world of fluid power. For years, MAPAL’s expertise has been in demand for the spool bore. The gap dimension with the spool depends on the accuracy of this bore, so that the hydraulic oil can only flow in the required direction without leaking. This is very narrowly defined in modern hydraulic valves. The roundness, cylindrical form, straightness and surface finish of this bore are therefore crucial.
Valve block

Machining requirements

  • Fluctuating cast allowance situation
  • Heavily interrupted cuts
  • Avoid ring formation during boring and ensure safe chip removal from the housing
  • Avoid macroscopic flaws on the control edges in the boring process
  • Very high demands on form and position tolerance
  • Constant stock removal before honing
  • Take part variance and limited tool storage places in the machining concept into account

Control valves

Control valves are mechanically or electronically actuated valves with several switch positions. Depending on the specified position of the spool along the control edges, a volume flow is set for operating the connected working equipment. The individual pressure compensator adjusts a constant load pressure drop via the supply control edge of the spool, so that a load pressure-independent volume flow control is achieved across the whole adjusting range, also in parallel operation (load compensation). The system must be leakage-free, to prevent accidental dropping of the load, even with parallel operation.

Bore machining

Application solutions

1 – Small and medium series with fixed tools

Initial situation at the customer

MAPAL Application solution 1

Valve housing EN-GJS-400-15 – spool bore

  • Individual orders, smaller and medium quantities
  • No option for tool setting
  • Short cycle times required
  • High machine hourly rates
  • Stable oscillating honing available
  • Tool concept adapted to several part versions

Details
2 – Large series with solid and adjustable tools

Initial situation at the customer

MAPAL Application solution 2

Valve housing EN-GJS-400-15 – spool bore and compensator bore

  • Large-scale series
  • Tool setting desired
  • High machine hourly rates
  • High costs for subsequent single pass honing

Details
3 – Small lot sizes – Reduced tool changes due to combination tools

Initial situation at the customer

MAPAL Application solution 3

Valve housing EN-GJL-300 – spool bore

  • Small lot sizes
  • Option for tool setting available
  • Too many/frequent tool changes
  • High machine hourly rates
  • High effort due to single pass honing process

Details
4 – Flexible honing on the machining centre

Initial situation at the customer

MAPAL Application solution 4

Valve housing EN-GJS-400-15 – Compensator bore / honing

  • Request for reduction of ancillary costs
  • Existing machining centre re-tooled to TOOLTRONIC
  • Honing for prototype manufacture, as well as small and medium-scale production runs
  • Requirement for saving the honing process on separate machine

Details
5 – Tool management

Initial situation at the customer

MAPAL Toolmanagement

Valve housing EN-GJS-400-15 – complete machining

  • High inventories
  • Processes in the tool-setting area not optimal, and incomplete data quality
  • Cost transparency is not sufficient
  • High fluctuation due to general lack of skilled workers
  • Problems with tool breakage
  • High tool costs

Details

Tool solutions

Piloting and boring
  • Pilotieren

    Solid carbide boring tool

    • Six margin lands for perfect roundness and straightness
    • Optimum chip flow and extended regrinding options through multicut technology and suitable coolant supply

  • Boring

    Solid carbide boring tool

    • Three cutting edges, six margin lands and special lead geometry
    • Straight bore, ideal chip flow und guide across the entire bore length

  • Boring

    Solid carbide boring tool

    • Six margin lands and special lead geometry
    • Straight bore, ideal chip flow und guide across the entire bore length
    • Reduced non-productive times due to two machining operations in one tool

  • Piloting and boring

    Multi-stepped boring tool

    • Radial and tangential indexable inserts
    • Pre-machining spool bore and completion of contours in one processing step

  • MAPAL Boring

    Double edge boring tool

    • Form cutting edges
    • Reliable machining of the contour
    • Easy handling with low cutting material costs

Control edge machining
  • Control edge machining

    Solid carbide circular milling cutter

    • Significant cycle time savings
    • Defined control edges without macroscopic flaws

  • Control edge machining

    Solid carbide profile tool

    • Highest accuracy and surface finish of control edges
    • Defined control edges without macroscopic flaws

Reaming and fine boring
  • Reaming

    Multi-bladed reamer

    • High cutting data
    • Perfect chip control due to left-hand twist and optimum coolant supply

  • Fine boring

    Fine boring tool

    • EasyAdjust system and guide pads
    • Reliable precision machining with easy handling without subsequent honing
    • Best cylindrical forms due to optimum guidance

  • Fine boring

    Fine boring tool

    • Indexable inserts and guide pads
    • Ideal for bar machining of highly accurate and long bores

Fine machining with honing
  • TOOLTRONIC

    MAPAL TOOLTRONIC

    • Significant shortening of production and cycle times
    • Greater contour accuracy

Milling
  • NeoMill-16-Face

    NeoMill®-16-Face

    • 16-edge indexable insert / 45°
    • First choice for cast iron and heat-resistant cast steel
    • ø area 63-200 mm / ap max. 4 mm
    • Low cutting forces despite a negative shape
    • Maximum economic efficiency for face milling

  • NEOMILL-8-CORNER

    NeoMill®-8-Corner

    • Eight-edge indexable insert / 90°
    • First choice for cast iron
    • ø area 50-200 mm / ap max. 8 mm
    • Maximum economic efficiency for shoulder milling

  • NEOMILL-4-CORNER

    NeoMill®-4-Corner

    • Four-edge indexable insert / 90°
    • Highly suitable for steel, stainless steel, cast iron and heat-resistant cast steel
    • ø area 25-100 mm / ap max. 10 mm
    • Multipass milling of high shoulder dimensions
    • Very low cutting forces despite a negative shape

Clamping
  • UNIQ Mill Chuck

    UNIQ Mill Chuck

    • Highly thermal stability from 80 °C even with very long milling cycles (over 240 minutes)
    • For high-performance milling operations up to max. 33,000 revolutions per minute
    • Highest process reliability

  • UNIQ DReaM CHUCK 4.5°

    UNIQ DReaM Chuck 4,5°

    • Hydraulic chuck with the original dimensions of a shrink chuck (DIN contour with 4.5°)
    • Application-oriented system design
    • Maximum process reliability and tool life
    • Faster und highly precise tool change

  • HB MILL CHUCK SIDE LOCK CHUCK

    HB MILL CHUCK SIDE LOCK CHUCK

    • Easy to handle thanks to use of a differential screw
    • Maximum economic efficiency and precision
    • Axial tool positioning can be defined using spring system
    • Optimum positioning of profile tools for control edge machining

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