by Bernie Otto
Advice on retrofitting your HMCs
To be in a good position to efficiently and economically address future milling application demands, manufacturers are well served by investing in machines that can easily expand as your business grows.
Although more expensive up-front, many manufacturers are moving towards horizontal machining centres (HMCs), as an alternative to vertical machining centres (VMCs), for the flexibility the horizontal solution provides today and for future growth. Benefits from HMCs include efficient chip evacuation, accessible three-side machining and the capability of having multiple parts on a fixture. Further, multi-pallet pools on HMCs provide many advantages such as: reduced setup times, longer run times, greater spindle up times and the potential of lights-out manufacturing.
Most HMC machines include the option of retrofitting pallets and larger ATC (Automatic Tool Changer) capacity in the field. Careful examination is required though, to ascertain that the retrofitting option can be easily and economically implemented.
Most standard HMCs include two pallets and the majority of machine tool manufacturers offer multiple pallet solutions (i.e. 3,5,8,10,12) that can be retrofitted in the field. However, several “expensive” challenges may be involved with this retrofit process including:
- The time necessary to perform the retrofit.
- It is possible that the HMC could be out of production for 7 -10 days due to sheet metal modifications and custom fitting that needs to be performed.
- Software issues. Perhaps the multi-pallet software will need to be upgraded. This process may lead to additional lost production time due to software availability issues, incompatibility problems due to not obtaining the proper software revision version and loss of current programs when the software is upgraded.
Along with expanding the pallets, you will need to add tool capability to increase the machine’s milling capabilities. At the time you invest in the HMC, it is a good idea to review the ATC (Automatic Tool Changer) capacity. A standard two pallet horizontal will come with 40—60 tools. This is usually not expandable in the field. An expandable system usually starts at 80 or 90 tools and can go up to 250 or 300 tools.
If machine tool expandability is something your business will need, it pays to investigate HMC solutions that can easily be retrofitted in the field. Efficient retrofitting can add up to significant savings in time and money. SMT
Bernie Otto is technical sales manager, Methods Machine Tools Inc., Sudbury, MA.