Written by Humphrey Carter on December 18, 2020 in feature News

CompoTech PLUS, spol. s r.o has developed a new hybrid metal and carbon fibre composite milling cutting disk in collaboration with HOFMEISTER – Innovation. The new composite four-disc milling cutter increases both the cutting speed and feed rate. The result is a high productivity hybrid milling tool that can operate 78% faster on the same milling centre than a standard steel two-disc cutter.

Key production benefits of the new hybrid four-disc milling tool include:

  • Lower inertia moment, resulting in lower energy consumption cost savings.
  • Lower thermal-mechanical load on milling machines
  • Better anti-vibration damping properties, increasing slot hole machining accuracy. 
  • Smoother machine operation, enabling a higher quality surface finish.
  • Significantly increased output rates and productivity.
  • The durability of the new hybrid tool is almost five times greater.
4 disk hybrid milling cutter

Exceeding Expectations

The new milling tool collaboration project was initiated by HOFMEISTER s.r.o. after receiving an inquiry for a four-disc milling tool from a leading European chain manufacturer looking to improve output rates and reduce production costs. By using CompoTech’s carbon fibre technology in the design and production, a new lightweight CF composite and steel hybrid milling tool was successfully developed with two additional cutting discs. The new four-disc hybrid tool was well within the specified Doosan Mecatec HM63H twin pallet horizontal machining centre’s 25kg maximum weight limit; this was not achievable using four conventional metal disc cutters, which individually weigh 7.93kg.

To further boost machining performance, the novel hybrid tool design included additional cutting inserts per disc. The hybrid milling tool has a total of 64 cutting inserts on four discs compared with only 24 on the standard two-disc milling cutter. The net result was vastly superior machining performance, reducing the machining time of a forged steel chain link component from 45 to 10 seconds, exceeding expectations.  

Comparative Testing

The comparative testing carried out during the project conclusively demonstrated that the new hybrid four-disc milling tool could be used for machining in precisely the same way as a conventional all-metal two-disc milling cutter, but with added machining speed and durability. These significant benefits more than justify the initial higher cost of the new hybrid cutter, which HOFMEISTER has estimated has an investment payback period of only around three months for a high volume producer. Table 1 shows details of the technical, operation and economic information comparing the two milling tools. 

Technical/
Operational/
Economic parameter
Current 2-disc milling tool solutionNew hybrid 4-disc milling toolNew hybrid tool benefit
Tool assembly weight
[Weight / disc]
15.85 kg
[ 7.93 kg ]
16.25 kg
[ 4.06 kg ]
4 hybrid discs within the max 25kg weight limit
Cutting inserts / disc
[Total inserts / tool]
12
[12 x 2 discs
= 24 total]
16
[ 16 x 4 discs = 64 total  ]
40 extra cutting inserts
Cutting Speed (vc)vc = 120 m/min (n= 190 min-1)vc = 180 m/min (n= 286 min-1)50% faster cutting speed
Feed rate (vf)    vf = 260 mm/min (fz= 0.11 mm)vf = 400 mm/min
(fz= 0.08 mm)
54% higher feed rate
Processing time per piece reduced by 78%.
tc   (machining time in seconds per piece)45 seconds10 secondsProcessing time per piece reduced by 78%.
4.5 times better productivity
(durability of cutting edge in nos. of parts)~ 250 pcs~1200 pcs> 4.8 times higher durability
Acoustic emission level during millingHigh (subjective)Low                   (subjective)Lower machine shop noise level
Quality of machiningSatisfactoryVery good
(without vibration chatter marks)
Better damping/ less  vibration improves machining accuracy
Investment cost comparison / Payback time~ €2 000~ €10 000 Payback on investment in approx. 3 months
Table comparing Composite Hybrid Cutter with Steel Cutter

Ing. Pavel Kožmín, PhD., Head of R&D for HOFMEISTER, commented: “This has been another excellent collaboration between the R&D teams from both companies. We have developed an even better performing milling tool than we originally expected thanks to the unique carbon fibre epoxy composite design and production capabilities of CompoTech. The new hybrid milling tool project has exceeded our customer’s expectations with the operational and commercial benefits provided.” 

This innovative new hybrid four-disc milling cutter tool offers manufacturers the opportunity to save time and money by achieving significantly higher unit output volumes using existing CNC milling centres, with lower overall production costs. Business benefits from using the new hybrid tool include debottlenecking, improving profitability, and delaying or avoiding the need for further capital investment to achieve growth targets.