They are not agents of social control. Social control as an element of social management

Let's consider what the process of standardization of adjustment work on CNC machines is and why it is needed.

Doing development complex processes processing workpieces for CNC machines and programs that control it, the main criterion is the norm of time for the manufacture of parts. Without it, it is impossible to calculate the salary for machine operators, to calculate such an indicator as labor productivity and equipment load factor.

Beginning the process

Typically, workers need to spend extra time on approach and retraction procedures, mode changes, and tool changes. Therefore, as part of the time spent on processing parts, the duration of the adjustment period is also taken into account. The rationing of labor begins with timing in the conditions of the operating machine. With the help of a stopwatch, the time spent is fixed to install one part on the machine, then remove it.

Minutes are spent on site maintenance, the immediate needs of the operator. When working on a turning-and-boring machine (single-column), it takes 14 minutes, and on two-column - 16 minutes.

What is included in the workplace service

The machine maintenance process includes:

organizational measures - inspection of the machine, its warming up, testing of equipment: running in the hydraulic system and CNC. It takes some time to get instructions and tools from the master along with the task (attire, drawing, software carrier); present the first received sample of the part to the Quality Control Department, lubricate and clean the machine during the shift, clean the place of work after its completion. Fixed time costs for the implementation of a complex of organizational works on turning and rotary equipment, in accordance with the norms, become 12 minutes. When additional maintenance efforts are required, an appropriate amendment is introduced;
technical measures - replacement of a tool that has become dull; adjustment of machines throughout the shift and adjustment. There are other obligatory works: in the course of the working process, chips must be constantly removed from the cutting or turning zones.

Time spent setting up the machine

The documents that reflect labor standards determine the time for setting up equipment, depending on its design. If the processing is performed on, the standards for installing and removing the cutting tool are taken as the basis for the calculation.

When it is necessary to perform a correction of the positions of the tools that process test parts, the period of processing the part is included in the duration of the preparatory phase.

The standards for setting up and maintaining automatic lathes are an important standard. They are laid in the total time for the production of one part and, accordingly, they form economic indicators workers and production in general.

Collections of regulatory documents

Normalizers of plants and factories where machines with numerical and program management, use in the calculation of working time the standards laid down in the documents:

unified tariff qualification handbook works;
All-Russian classifier of occupations for workers;
Unified qualification directory of positions of managers and specialists;
Collections of labor standards for the work that is performed to set up the programmable equipment.

IMPORTANT! All this normative literature is basic for managers of all levels and personnel structures.

Without it, it is impossible to determine the time to perform certain amounts of work, the number of specialists that need to be involved, and the time standards used in the development of maps for technological processes.

Setup cards

For a machine of a certain type, a strictly normalized duration of production setup operations is developed and a setup chart is assigned to it. When developing, many factors are taken into account in order to obtain the final picture.

The norm of time allocated to the machine operator provides for:

the specifics of the procedure for diagnosing the machine park;
the presence of several options for the adjustment mode;
compliance with service requirements.

In order to determine the rate of labor intensity (unit of measurement - man-hours or man-minutes) of any work, take into account the time during which one part is processed on this machine. The rater also operates with the concept of a piece norm of time, which determines the total time in accordance with the types of work.

Accordingly, the total time is divided into main and auxiliary segments, organizational maintenance activities; transitions between machines during multi-machine maintenance; monitoring the work process; pauses due to equipment operation.

The Institute of Labor has the results of standardization for the equipment of milling and drilling and boring groups, lathes and automatic lines are provided with standards.

IMPORTANT! Knowing the standards, managers determine the degree of employment of the worker (his labor intensity is calculated), distribute work zones and set the optimal working pace.

Multi-Station Maintenance - Timing Approaches

In factories with a high degree of automation, multi-machine maintenance of CNC machines is practiced (forms of labor organization - in teams, units and individually). Accordingly, service areas are also fixed.

Multi-machine maintenance provides for the time spent on:

preheating of equipment at idle, if this is provided for by the operating instructions for turning equipment;
work according to the machine control program with workplace maintenance;
installation of blanks, removal of parts and control of their quality;
fulfillment of personal needs of the operator;
loss of the planned plan;
implementation of the preparatory and final stage of work;

The classification of multi-machine labor is carried out according to work; zones, types and systems; functions performed by the multi-machine.

Machine Maintenance Systems and Methods

The enterprises practice a cyclic maintenance system - at workplaces and production lines for machine tools that have an equal or similar length of time for which the part is processed. It is characterized by a constant stream of demands. The non-cyclic is that the operator immediately goes to service the machine, where the automatic mode of operation has ended. It is characterized by occasional demands for service.

Other methods are also possible:

watchdog - the worker monitors the entire machine park assigned to him, simultaneously determining the need for maintenance. With priority, the order in service is determined by the operator, based on the cost of the machined parts.
route, it consists in bypassing a group of machines along a predetermined route.

Maintenance of several machines with the same or different duration of workpiece processing operations has its own nuances. However, all of them are subject to rationing during the careful development of the production process.

Conclusion

On CNC machines, to standardize setup work, you need to take into account many nuances when calculating the duration of various operations.

Defining final time processing a part on one machine (we are talking about turning or), the norms are also calculated for the entire machine park.

The use of machine tools with numerical control (CNC) is one of the main areas of automation of metal cutting, allows you to free up a large number of universal equipment, as well as improve product quality and working conditions for machine operators. Fundamental difference these machines from conventional ones is to set the processing program in mathematical form on a special program carrier.

The norm of time for operations performed on CNC machines when working on one machine consists of the norm of preparatory and final time and the norm of piece time:

The preparatory-final time is determined by the formula

T pz \u003d T pz1 + T pz2 + T pr.obr

The norm of piece time is calculated by the formula

T c. a \u003d T o + T mv,

The main (technological) time is calculated on the basis of cutting conditions, which are determined according to the General Machine Building Standards for time and cutting conditions for standardizing work performed on universal and multi-purpose machines with numerical control. According to these standards, the design and material of the cutting part of the tool is selected depending on the configuration of the workpiece, the stage of processing, the nature of the allowance to be removed, the material being processed, etc. It is preferable to use a tool equipped with hard alloy plates (if there are no technological or other restrictions on their use). Such limitations include, for example, interrupted machining of heat-resistant steels, machining of holes with small diameters, insufficient speed of rotation of the part, etc.

The depth of cut for each stage of processing is chosen in such a way as to ensure the elimination of machining errors and surface defects that appeared in the previous stages of processing, as well as to compensate for errors that occur at the current stage of processing.

The feed for each stage of processing is assigned taking into account the dimensions of the surface to be machined, the specified accuracy and roughness of the material being machined, and the depth of cut selected at the previous stage. The feed selected for the roughing and semi-finishing stages of processing is checked by the strength of the machine mechanism. If it does not meet these conditions, it is reduced to a value allowed by the strength of the machine mechanism. The feed selected for the finishing and finishing stages of processing is checked according to the condition for obtaining the required roughness. The smallest of the innings is finally chosen.

Cutting speed and power are selected according to previously defined tool parameters, depth of cut and feed.

The cutting mode at the roughing and semi-finishing stages is checked by the power and torque of the machine, taking into account its design features. The selected cutting mode must satisfy the following conditions:

N<= N э и 2М <= 2М ст,

where	N	-	power required for cutting, kW;
	N e	-	effective power of the machine, kW;
	2M	-	double cutting torque, Nm;
	2M st	-	double torque on the machine spindle, allowed by the machine according to the strength of the mechanism or the power of the electric motor, Nm.

Double cutting torque is determined by the formula

If the selected mode does not meet the specified conditions, it is necessary to reduce the set cutting speed according to the value, allowable power or torque of the machine.

Auxiliary time associated with the execution of an operation on CNC machines provides for the implementation of a set of works:

related to the installation and removal of the part: "take and install the part", "align and fix"; "turn on and off the machine"; "unfasten, remove the part and put it in a container"; "clean the device from chips", "wipe the base surfaces with a napkin";
associated with the execution of operations that were not included during the cycle of automatic operation of the machine according to the program: "turn on and off the tape drive mechanism"; "set the given relative position of the part and the tool along the X, Y, Z coordinates and, if necessary, make adjustments"; "check the arrival of the tool or part at the point specified after processing"; "advance the punched tape to its original position."

In general, auxiliary time is determined by the formula

T in \u003d T v.y + T v.op + T v.meas,

Auxiliary time for control measurements is included in the piece time only if it is provided for by the technological process, and only when it cannot be blocked by the cycle time of the automatic operation of the machine.

Correction factor (K t in) for lead time manual auxiliary work, depending on the batch of machined parts, is determined from Table. 12.7.

Table 12.7. Correction factors for non-productive time depending on the size of the lot of workpieces in series production. Map #1

item number	Operative time (T c.a + T c) min., up to	Type of production
		Small-scale			Medium series
		Number of parts in a batch, pcs.
		6	10	16	25	40	63	100	160	250
1	4	1,52	1,40	1,32	1,23	1,15	1,07	1,00	0,93	0,87
2	8	1,40	1,32	1,23	1,15	1,07	1,10	0,93	0,87	0,81
3	30 or more	1,32	1,23	1,15	1,07	1,00	0,93	0,87	0,81	0,76
Index		a	b	in	G	d	e	well	h	and

Maintenance of the workplace includes the following

When developing a technological process for processing parts and control programs for CNC machines, one of the main criteria for assessing the perfection of the selected process or optimizing it is the rate of time spent on processing a part or batch of parts. It is also the basis for determining the salary of a machine operator, calculating the load factor of equipment and determining its productivity.

The estimated rate of time (min) for processing one part (labor input) is determined from the well-known formulas:

piece time T pcs \u003d T o + T m.v + T v. y + T obs,

piece-calculation time

The total value of the operation time with all movements can be conditionally called the time of the tape T l \u003d T o + T m.v,

where T about - the total technological time for the entire operation of the transitions, min; T m.v - the element-by-element sum of the machine auxiliary time for processing a given surface (approaches, retractions, switching, turns, tool changes, etc.), taken from the machine's passport, depending on its technical data and dimensions, min.

The values of these two components of the norm of processing time are determined by the technologist-programmer when developing a control program that is recorded on punched tape.

The value of T l is practically easily checked when the machine is running using a stopwatch as the time from the start of processing in the automatic mode of starting the tape until the end of the processing of the part according to the program.

Thus, we obtain: operational time T op =T l + T v.y;

piece time T pcs \u003d T l + T v.y + T obs,

where T v.y - the time of installing the part on the machine and removing it from the machine, taken depending on the mass of the workpiece, min;

T obs \u003d T op * a% / 100 - time for maintenance of the workplace, personal needs and rest of the operator (accepted as a percentage of the operational time), min. For single-column lathes take a = 13%, i.e. T obs = = 0.13 T op, and for two-column T obs = 0.15 T op; then T pcs \u003d T op X (1 + a% / 100) min.

Scope of work for the maintenance of the workplace.

1. Organizational maintenance - inspection, warming up and running-in of the CNC device and the hydraulic system of the machine, equipment testing; receiving a tool from a master or adjuster; lubrication and cleaning of the machine during the shift, as well as cleaning the machine and workplace at the end of work; presentation of a test part to the Quality Control Department.

2. Maintenance - change of dull tool; input of tool length compensation; regulation and adjustment of the machine during the shift; removal of chips from the cutting zone during operation.

If the number of parts obtained from one workpiece on a lathe exceeds one and is equal to q, then when determining T pcs, it is necessary to divide T by the number of parts received q.

T p.z - preparatory and final time (determined for the entire batch of parts launched into processing P z). It consists of two parts.

1. The cost of a set of organizational work that is carried out constantly: the machine operator receiving a job assignment (order, drawing, software carrier) at the beginning of work and handing them over at the end of work; instructing the master or adjuster; installation of the working bodies of the machine and the clamping device in the initial (zero) position; installation of the program carrier - punched tape in the reader.

For all these works, the standards for lathes and vertical lathes allocate 12 minutes. If the design features of the machine tool or CNC system require, in addition to those listed, additional work, then their duration is experimentally and statistically determined and an appropriate correction is introduced.

2. The time spent on the performance of adjustment work, depending on the design features of the CNC machine. For example, for single-column lathes with CNC, the following time standards are accepted: to install four cams on the faceplate of the machine or remove them - 6 minutes; to install the fixture on the faceplate of the machine manually - 7 minutes, with a lift - 10 minutes; for installation of one cutting tool in the tool holder 1.5 min, its removal - 0.5 min; to install one tool holder in the turret head 4 min, removing it - 1.5 min; for installation at the beginning of work in the zero position of the crossbar and calipers - 9 min.

If the position of the tools is adjusted during the processing of a test part, then the time for processing the test part is also included in the preparatory and final part.

The norm of time for performing operations on CNC machines when working on one machine (N VR) consists of the norm of preparatory and final time (T PZ) and the norm of piece time (T W)

where: T CA - the cycle time of the automatic operation of the machine according to the program, min;

T In - auxiliary time to perform the operation, min;

and those, a org, a ex - time for technical and organizational maintenance of the workplace, for rest and personal needs during one-station service,% of the operational time;

K t in - correction factor for the time of manual auxiliary work, depending on the batch of workpieces.

The cycle time of automatic operation of the machine according to the program is determined by the formula:

where: T O - the main (technological) time for processing one part, min;

T MB - machine-auxiliary processing time according to the program (for approaching and retracting a part or tool from the starting points to the processing zones; setting the tool to a size, changing tools, changing the magnitude and direction of feed, time of technological pauses, etc.), min .

The main processing time is:

where: L i - the length of the path traversed by the tool or part in the feed direction during processing of the i-th technological section (including infeed and overrun), mm;

S mi - minute feed in this technological section, mm/min.

The auxiliary time for the operation is defined as the sum of the times:

where: T V.U - time to install and remove the part manually or with a lift, min;

T V.OP - auxiliary time associated with the operation (not included in the control program), min;

T V.ISM - auxiliary non-overlapping time for measurements, min;

Machine auxiliary time associated with the transition, included in the program and related to the automatic auxiliary operation of the machine, providing for the supply of a part or tool from the starting point to the processing zone and withdrawal; setting the tool to the processing size; automatic tool change; turning the feed on and off; idle strokes during the transition from processing one surface to another; technological pauses provided for when a sharp change in the direction of feed, checking dimensions, for inspecting the tool and reinstalling or refastening the part, is included as constituent elements during the automatic operation of the machine and is not taken into account separately.

The preparatory and final time standards are designed for setting up CNC machines for processing parts according to the implemented control programs and do not include additional programming directly at the workplace (except for machines equipped with operational program control systems).

The norm of time for setting up the machine is presented as the time for receiving preparatory and final work for processing a batch of identical parts, regardless of the batch, and is determined by the formula:

where: T PZ - the norm of time for setting up and setting up the machine, min;

T PZ 1 - the norm of time for organizational training, min;

T PZ 2 - the norm of time for setting up a machine, fixture, tool, software devices, etc., min;

T PR.OBR - the rate of time for trial processing.

The time for preparatory and final work is set depending on the type and size group of equipment, as well as taking into account the features of the program control system, and is divided into time for organizational training; for setting up the machine, tool fixtures, software devices; for a trial pass through the program or trial machining of the part.

The scope of work for organizational training is common to all CNC machines, regardless of their group and model. Time for organizational preparation includes:

receipt of an order, drawing, technological documentation, software carrier, cutting, auxiliary and measuring tools, fixtures, blanks before the start and handing them over after processing a batch of parts at the workplace or in the tool pantry;

familiarization with the work, drawing, technological documentation, inspection of the workpiece;

master's instruction.

The composition of the work on setting up the machine, tools and fixtures includes methods of work of a setting nature, depending on the purpose of the machine and its design features:

installation and removal of fasteners;

installation and removal of the block or individual cutting tools;

setting the initial modes of operation of the machine;

installing the program carrier in the reader and removing it;

zero position adjustment, etc.

For an operation performed on a CNC machine (015), we calculate the time standards according to the method given in the literature, part 1, and for the rest of the operations, according to the enlarged method given in the literature.

Piece time is determined by the formula:

where T c.a. - cycle time of automatic operation of the machine according to the program, min. Includes the main time T about the operation of the machine according to a given program and T m.v. machine-auxiliary time.

T ca \u003d UT mv + UT o (1.68)

Auxiliary time is defined as the sum of the time to install and remove the part, the time to fix and unfasten the part, the time to measure the part, and the time to operate the machine.

T in \u003d T us + T in.op. + T v.meas. (1.69)

where T us - time to install and remove the part, min;

T v.op. - auxiliary time associated with the operation. Includes time for control, installation and removal of the shield that protects against splashing with emulsion during processing, checking the return of the tool to a given point after processing, min;

T out - time to measure the part. This time is excluded from the calculation, as it is covered by the processing of the machine according to the program for CNC machines, min.

The time for maintenance of the workplace is made up of time for rest, for organizational maintenance and time for maintenance of the workplace.

T those - time for maintenance of the workplace.

Consists of: time for adjustment and adjustment of the machine during operation; time to change a dull tool; time for chip removal during operation. It is expressed as a percentage of the operating time.

T org - organizational maintenance of the workplace.

Consists of: time for laying out the tool at the beginning of work and cleaning it at the end of the shift; time for inspection and testing of the machine at the beginning of the shift; time for cleaning and lubricating the machine.

T otd - time for rest and personal needs.

Piece-calculation time is determined by the formula:

where N is the program for launching parts per year, pcs.; N=2400 pcs.,

S is the number of launches per year;

T p.z. - preparatory and final time;

T p.z. \u003d T p.z.1 + T p.z.2 + T p.z.3, (1.72)

where T p.z.1 - time for organizational preparation, min;

T p.z.2 - time to set up the machine, fixtures, CNC, min;

T p.z.3 - time for trial processing, min:

T p.z.3 \u003d T p. arr. +T c.a. (1.73)

Figure 1.10 - Cyclogram for determining the operating time of the machine according to the program for turning operations with CNC 015

Machine 16K20T1:

Fixation time of the turret T IF =0.017 min;

The time of rotation of the turret by one position T ip = 0.017 min

To determine the time of automatic operation of the machine according to the program, we will compile Table 1.9.

Table 1.9 - The time of automatic operation of the machine according to the program. Operation 015

Section of the trajectory or position numbers of the previous and working positions	Increments along the Z axis Z, mm	Increments along the X X axis, mm	The length of the i-th section of the trajectory	Minute feed on the i-th section of the trajectory, mm/min	The main time of automatic operation of the machine T about, min	Machine-auxiliary time T mv, min

The total cycle time of the automatic operation of the machine according to the program when processing the part at operation 015:

T c.a. =5.16+0.71=5.87 min.

Time to install and remove the part, T us = 0.24 min

Auxiliary time associated with the operation, T v.op =0.15+0.03+0.05=0.23 min;

Time to measure the part, T in meas = 0 ? time is covered by the processing of the part on the machine according to the program.

Auxiliary time:

T in \u003d 0.24 + 0.23 + 0 \u003d 0.47 min;

Operation time:

T op \u003d 5.06 + 0.47 \u003d 5.53 min;

and those + a org + a otd \u003d 8%

Determine the piece time for operation 015:

We determine piece-calculation time:

Time for organizational preparation:

T p.z.1 =13 min;

Time to set up a machine, fixture, tool, CNC:

T p.z.2 \u003d 19.4 min;

Time for trial processing:

Тp.z.3=3.54+5.06=8.6 min;

Total preparatory and final time:

T p.z. =13+19.4+8.6=41 min;

Part lot size:

S=12? (v.1 p.604)

Table 1.10 - Results of calculating the norms of time