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News Release from: Costruzioni Meccaniche Caorle | Subject: CM132 End-Working Machine
Edited by the Manufacturingtalk Editorial
Team on 11 September 2002
Managing an island with 100s of shafts
To machine hundreds of shafts quicker, an NC 'island' completes in one cycle by using an end- working machine to carry out the first machining operations and so speed up subsequent operations.
To obtain improved machining of hundreds of shafts in a faster time, an automatic 'island' completes a workpiece in one cycle by using an end-working machine to carry out the first machining operations and so speed up the following operations Thirty years on from when the Italian company Montanari Giulio began production of different types of pulleys and other mechanical components for elevators, the company is now one of the most important manufacturers of hoists and components for elevators
This article was originally published on Manufacturingtalk on 22 Mar 2002 at 8.00am (UK)
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Located in Modena, the company's growth has been constant.
It now has an area of 23,000m2 of which 8000m2 are covered.
The range of its products has grown year by year and they have always been successful on the worldwide markets.
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Nowadays the most important sector regards hoists, which are produced in various types, from the traditional ones to the new compact screw driven hoists and the innovative Gearless MDD.
The latter uses brushless technology and assures a higher comfort of working in compact dimensions.
Apart from hoist, many other components regarding driving and setting of elevators are manufactured: oil-dynamic unit, speed limiters, rope-ends, brake parachute, electronic speed regulators, supports and sliding blocks, derivation and postponement pulleys.
The bigger part of the turnover derives from export sales, with an important presence in more than 40 countries.
Emerging markets are the Arabic area and the South East Asia.
Particular attention has been paid to the quality and the company has obtained the certificate of conformity ISO 9001 from the well know German Institute TuV.
In order to honour the commitment of guarantee a high constant standard level of production, together with the professional growth of the employees, the Modena company invests extensively in plant modernisation and machine tools.
The working automatic 'island', which has recently been commissioned in Modena, was entirely conceived by Montanari.
Special pallets and customised software (in-house products) are used together with products supplied by other companies, which are a lathe, a robot and a 6-head end-working machine made by Caorle.
The company's 'daily bread' is the shafts for approximately 800-900 reducers per month.
There are three shafts per reducer, which means thousands of pieces; counting motor shafts, worm screw and shafts called "slow motion"(those with a lower speed compared to the standard speed of the plant).
The machining of each shaft starts from a bar that gives the required shape and dimension.
On average, with a cycle of 8 minutes per piece, the NC island is able to work up to one hundred shafts unattended as regards to length.
"We machine different types of shafts," says Giovanni Tempestini, who is responsible for the manufacturing plants at Montanari's, " but the machining is basically the same.
At the input we have pallets with raw items; the robot takes the raw shaft, measures it and loads it into the end-working machine.
When the machining is finished it brings the shaft and places it into the bore blowing machine in order to clean the holes and then, it loads it into the lathe, but only after having printed the required code." He continued: "This production facility, integrated with the Caorle CM132 End-Working Machine, allowed us to drastically change our strategies for the production of shafts.
The Caorle end-working machine carries out facing of the ends and it makes the centres needed as a reference from the lathe, which does the last part of machining.
The main advantage is to obtain completely finished shafts according to the categories of precision needed." Said Tempestini: "By working with the 'strategies of centres', all the risks of eccentricity errors have disappeared.
A perfect centre, milled on the extremities of each shaft, either as a position or as a dimension, is for us extremely important; the end-working machining allows you to hold the shaft in between the lathe centres for the complete finishing, without any additional machining." It was not long ago when shaft machining was made with a lathe working using two set-ups and without centre locations.
So that, there was a need to clamp the piece by means of the spring collet for the first machining on one side; and then you had to do the same for the other side.
The Caorle CM132 reduces machining time, saving at least 50% of working time that was necessary for carrying out the total machining.
Another benefit you have is the overall quality of the finishing.
"After a machining in two set-ups with a lathe," said Tempestini, "It was always necessary to add a grinding operation, this was because, between the first and the second set-up, it was inevitable that some geometric errors would occur, even if they were microscopic.
The precision we need is really high, on the scale of the hundredth of mm." He explained: "This really low tolerance is absolutely necessary with regards to the nature of our product, which has to rotate under power: in this case a minimum defect will cause unacceptable lack of balance: it is a 'must' to be able to guarantee the concentricity of the diameters.
Now, the shaft comes out from the end-working machine with its centres perfectly calibrated and the lathe is able to machine it in only one phase, and without any grinding." The Caorle CM132 is a machine tool with three independent heads on each axis, and with a motor for each spindle, and it is double in every respect.
The machine is equipped with two self-centering vices, one milling cutter and two drills each side.
The ISO 50 spindle is powered by an 11kW motor and it usually carries out the milling phase.
The first ISO 40spindle, with a 4kW motor power, can execute centering, drilling, chamfering and neck turning.
The second ISO 40spindle, is equipped with an encoder for rotation control, and is able to execute 'rigid' tapping.
All spindles are driven by AC brushless servomotors with digital inverters, which provide the speed variation while maintaining high torque and power values.
These spindles are also equipped with a rapid hydraulic activated unclamping device.
"The CM132," said Tempestini, "Is extremely flexible; it is a machine tool of an optimum level, and from my point of view, it is one of the best of its field.
We could have saved some money, by placing into the automatic island, some cheaper machines, such as hydraulic machines, or used a three-spindle machine driven by only one motor, but we would have had to have been satisfied with a lower flexibility level." Concluding, Tempestini commented: "The only observation we had to note after positioning the CM132 was regards the longer working cycle of the lathe, which causes waiting time for the end-working machine and periods in which it stays simply stopped.
It is our aim to make optimum use of its speed and its precise machining by placing another lathe into the island in the near future, in order that the CM132 can serve two lathes at the same time and realise better overall efficiency." The Caorle CM132 is a model of End-Working machine for bars, forgings and tubes with a standard working length of 1500mm.
The bed is manufactured of thick section, heavy-duty steel plate, welded and normalised.
Strategically located reinforcement ribs are placed for the greatest possible machine integrity and stability.
It incorporates specific slides conceived for an easy transferring of chutes towards the belt type chip conveyor.
The two saddles of the operating units slide on a precision hardened and ground guide ways; above the same ones are positioned the self-centering vices.
Two independently powered and horizontally opposed spindle-machining units are controlled by two NC transversing axis.
They are mounted on separate cast iron saddles with precision hardened and ground guide ways, which are automatically lubricated from a central lubrication system.
Each machining unit saddle features two longitudinal independent box-type guideways.
They are driven and positioned by precision ballscrew and AC brushless servomotors, with feedback to the CNC unit.
The functions of each spindle are programmed as individual machining processes, and are able to carry out dissimilar cutting operations simultaneously.
Workpiece clamping is actuated via a pair of horizontally mounted self- centring vice jaws.
These jaws are positioned by means of the displacement of the working units and they are blocked on the chosen position by means of a hydraulic system.
The precision heavy duty hardened and ground vice jaws can hold heavy workpieces.
The hydraulic systems is composed by a free standing centralized power pack, complete with tank, pump, filter, electro solenoid valves and with machine interface.
Coolant is piped to each spindle and dedicated valves control the flow (internal and external).
The NC operates the machining cycles directly and the interface with the operator is in an industrial PC for an easy and friendly programming.
The operator has only to supply the required information, as for instance: workpiece diameter/length, depth and diameter of the holes, etc.
A virtually unlimited storage of programs and the opportunity of loading them just by opening a 'window' in another facility of our software.
On the CM132 located at Montanari's site is customised software for checking tooling life.
Note: The original article (in Italian language) is published in September 2002 issue of the magazine "Macchine Utensili"(Machine Tools) published by Tecniche Nuove.
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(This was Manufacturingtalk's Top Story on 10 September 2002).
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