Mark Jones, MD, says: “A bar feeder seems like a relatively simple device. It is the most common automation accessory for high volume turning, it provides a reliable way of delivering material to the machine tool for extended periods of time, saving an operator from continually loading stock into the chuck. However, in reality bar feeders differ from one to another, and the feeding solutions developed by Cucchi Giovanni make them more suitable to high efficiency workshop environments.” 

Products, such as the DB-EVO bar feeder for single-spindle lathes, DMB/F and the CMSP units for multi-spindle turning machines, highlight the company’s mantra of ‘innovation and simplicity’.

Designed to support efficient unattended or minimally manned production operations, the DB-EVO hydrostatic bar feed system offers continuous, controlled automatic feeding of bars/tubes of any profile, without the need for lubrication. The hydrostatic design allows raw stock material to rest in a series of guide supports, made of an advanced plastic material. The supports resemble clamshells, with a top half and a bottom half that close around the stock to hold it in place and provide stability during the turning operation. These guide supports will generally accept a wide range of sizes and are designed to be changed very quickly when required. 

Standard stock material lengths of 1300, 1700 and 3300mm can be accommodated without any bar preparation, in diameters from 10mm incrementally to 120mm diameter, and are automatically loaded in just 3 to 6 seconds. 

Matching the performance of modern turning centres the DB-EVO can rotate at high speed without damaging the surface of the stock material, irrespective of the type of material and its profile (round, hexagonal, square, rectangular, oval, and so on) due to the use of reduction tubes in the lathe spindle and polyurethane bar retaining sleeves that spin on ball bearings mounted on fixed and moving steadies.

Developed to minimise the production floorspace required, the bar feeders feature Siemens PLC systems and touch-screen display to control each function of the loader. Bar diameters range from 3 to 80mm depending upon model, while the standard maximum bar lengths of 3300 or 4100mm can be customised. 

Guideways for the raw material are manufactured from reinforced nylon and have a high degree of resistance to the wear and abrasion caused by the rotation of the raw material, even if the bars have an irregular profile. The surface of soft materials is not marked or scored and, as the guideways are bayonet coupled and easily interchangeable with the aid of a special key, there is no need to disassemble the bases that anchor the drum. Replacing the guideways for smaller bar diameters is therefore quick to achieve. Vibrations and noise levels can be reduced by about 70%. This is mostly due to the fact that the guideways are assembled by slotting together and therefore, with their ends crossing, form a perfectly cylindrical channel. So, the bar stock does not encounter any breaks or opening and can reach high rotation speeds without collisions. 

Bar storage is a slant feed gravity rack for the DBM or a bundle for the DBMF with a 1200 kg capacity. Bar loading time is just 6 to 14 seconds depending on the configuration of the system.   

Also designed to enhance multi-spindle turning operations, the company’s CMSP multi-spindle feeder combines advanced solutions. At just 450mm longer than the stock material length of 3.3 or 4m, the standard version of the loader has a tilted bar magazine in the upper part, with the optional possibility of a bar bundle magazine with a capacity of 1200kg.  

Loading of the bar in the carrier channel and its subsequent feeding are fully automated. Feeding is performed by two hydraulic motors; the first inserts the bar in the spindle of the lathe and the second for feeding. The diameter of the bars which can be loaded can be changed in a few minutes, merely by replacing the bar feeder collets and adjusting the bar centring devices.

The pneumatically controlled bar centring device allows perfect alignment of the bar just before it enters the spindle of the lathe, eliminating impact and vibrations, and considerably reducing noise and increasing machining precision. 

Supporting efficient operation a remnant pick-up device extracts the last crop end of the raw material from the collet of the bar feeder rod and unloads it into the rear part of the loader, checking whether it has been recovered and unloaded by the collect and stopping the lathe in the event of a fault.

An example of the latest bar feeds will be exhibited at MACH 2016 (NEC, Birmingham, 11th to 15th April, Hall 5 Stand 5304).