Every day companies need to be more productive; that is to say, to obtain effectiveness and efficiency, therefore, it is an essential purpose to reduce the losses that they can have in the production process.
This work shows, in the footwear production process, the determination of various inspection points to reduce losses and deficiencies in the same, as well as the establishment of the control limits that must exist. In addition you can see the exemplification of everything raised.
INTRODUCTION.
This system of statistical regulation of the footwear process has been applied in the Manuel del Toro Footwear Company of the Province of Matanzas.
The objective of this work is given in the detection of the defects that arise in the different operations of the process, to influence the causes that originate them and in this way reduce the defective production in the process, as well as the effects on the product finished.
In our case, for its statistical regulation, we decided to use control charts, which constitute the fundamental tool for controlling the process.
DEVELOPING.
In order to exemplify this work, the study carried out in Workshop 101 "Samuel Fernández" of said company has been taken, in which men's dress footwear is produced, which constitutes one of the fundamental productions of the company.
The footwear production flow is made up of 6 departments, broken down as follows:
- Cutting Department Preparation Department Assembly Department Floor Department Auction Department Packaging Department
To carry out this work, the following steps have been taken:
- An analysis of the operations carried out in each of the previous departments was carried out, indicating where all the possible defects to arise in each operation were nominalized.These defects have been classified as critical, major and minor, according to the provisions of NC 92 - 01 Quality Control. Terms and definitions, as well as the classification of defects that appears in the specification standard that covers said product.The causes that originate each of the defects have been determined, which are given by three fundamental factors: man, materials raw materials or equipment.The consequences that each of the defects could cause have been determined, which were caused by the return of the footwear to be reprocessed or by the impact of this on the finished product.5 inspection points have been established in key places of the process, allowing to detect defects originated in previous operations and avoiding that defects may overlap due to some operation.
The inspection points have been located as follows:
Point No. 1: After the pieces have been lowered.
Point No. 2: After the operation turn liners.
Point No. 3: After performing the operation of sewing the mask.
Point No. 4: After the planting operation is carried out.
Point No. 5: After applying the second coat of adhesive.
Point No. 6: After the operation of sanding the heel.
Point No. 7: 100% inspection for the classification of the product in quality classes.
- For the statistical regulation of the process, it has been decided to implement control charts by demerits, taking into account that in the footwear production process the defects that originate can be critical, major and minor. Two models have been designed: the CC - 1 for the collection of information at inspection points 1 to 5 and CC - 2 for the results of the final classification. The mechanisms to follow have been established to take corrective measures based on the results obtained.
The procedure followed to establish the demerit control charts is set out below.
The method established for demerit control charts raises a weight for each type of defect, assigning demerits based on the severity of the defect.
This weighting will depend on the type of product analyzed, in our case, the weighting coefficients were determined from the average economic implication caused by the presence in the footwear of each of the types of aforementioned defects.
The formulas used to calculate the weighting coefficients are the following:
K 1 = 100
K 2 = (V 1 - V 2) 100 / V 1
K 3 = 100 / V 1
Where:
K 1: Coefficient of critical defects.
K 2: Coefficient of major defects.
K 3: Coefficient of minor defects.
V 1: Wholesale unit sale value of first-class footwear.
V 2: Wholesale unit sale value of second-class footwear.
Calculation of the Control Line and the Control Limits.
Sean:
d 1: Number of critical defects.
d 2: Number of major defects.
d 3: Number of minor defects.
The number of total demerits (D) that would be had in a series of samples analyzed, considering the weighting explained, would be the following:
D = K 1 d 1 + K 2 d 2 + K 3 d 3
This total number of demerits is used in relation to the unit of the product, which in our case is the pair of shoes.
Control Line:
U = K 1 (d 1 / N) + K 2 (d 2 / N) + K 3 (d 3 / N)
N: Number of units analyzed in the period.
That is:
U = K 1 U 1 + K 2 U 2 + K 3 U 3
Control Limits:
LC = U + - 3 б U for a 99.73% confidence level.
Where:
Cs = (K 1) 2 U 1 + (K 2) 2 U 2 + (K 3) 2 U 3
n: sample size.
The value of C is based on the theorem of the linear combination of several variables where:
U = K 1 U 1 + K 2 U 2 + K 3 U 3
б 2 U = K 1 б 2 U1 + K 2 б 2 U2 + K 3 б 2 U3
Taking into account that the Poisson Distribution E (x) = (x) we can say that:
U = √ K 1 2 U 1 + K 2 2 U 2 + K 3 2 U 3 / n
Therefore, taking into account the criteria set out in NC 92 - 08:80 Quality Control. Attribute Control Charts, where it is stated that the size of the rational subgroups and the interval should be such that approximately 5% of the production is inspected, so in this case it was decided to establish a frequency of 3 times per shift to each inspection point to have a greater representativeness and the size of the subgroups was calculated as follows:
n = (0.05 N) / 3
n = (0.05 x 900) / 3
n = 15 pairs
Where:
n: Size of each rational subgroup.
N: production of pairs of footwear for one shift.
The following is an example of inspection point No. 2.
Defects to Control:
- Critics:
Open seams.
Split piece when hemming
Lining not according to the cut number.
- Greater:
Marked outside the guide.
Deviation at heel join seams from 2 to 5 mm.
General seam deviation from 2 to 4 mm.
Uneven hem + - 4mm
Seam to the edge of the piece.
Skipped seams.
- Minors:
Bead joint seam deviation up to 3mm
General seam deviation up to 2mm
Poorly seated on the heel.
Sew off the mark.
Leave burr when trimming
Trim lining very to the edge.
- Inspection place.
It will be inspected after the liner flipping operation.
- Sample size.
15 pairs of shoes will be taken at random.
- Inspection Frequency.
The inspection will be carried out 3 times a day.
- Measurement means to be used.
Graduated ruler with different measurement standards.
- Establishment of the Control Chart.
30 rational subgroups of size 15 were taken, the results were tabulated in Table No. 2 and processed using a computer program that was developed to facilitate the calculations of the control line (U). The control limits (LC) and the variability (б U).
- The values obtained have been:
LSC = 45,280
LCC = 19,948
LIC = 0
б U = 8.444
Next, we will show Control Graph No. 2 with the values of the rational subgroups raised.
As can be seen in the graph, no value is outside the limits, so these will be the limits to be used.
Table No. 2
| Defects | Found | ||||
| No. of Subgroup. | Date | Critics | Greater | Minors | Number of Demerits per Unit |
| one | 05 - 05 | two | 8 | 6 | 25,600 |
| two | 05 - 05 | one | 6 | 7 | 16,533 |
| 3 | 05 - 05 | one | 7 | 4 | 17,066 |
| 4 | 05 - 06 | one | 7 | 8 | 18,133 |
| 5 | 05 - 06 | two | 13 | 14 | 34,400 |
| 6 | 05 - 06 | 0 | 14 | 13 | 22,133 |
| 7 | 05 - 07 | one | 14 | 13 | 28,800 |
| 8 | 05 - 07 | one | two | 10 | 12,000 |
| 9 | 05 - 07 | 0 | 8 | 6 | 12,266 |
| 10 | 05 - 08 | two | 7 | 7 | 24,533 |
| eleven | 05 - 08 | one | 10 | 7 | 21,866 |
| 12 | 05 - 08 | 3 | 3 | 5 | 25,333 |
| 13 | 05 - 11 | one | 7 | 6 | 17,600 |
| 14 | 05 - 11 | one | 9 | 6 | 20,266 |
| fifteen | 05 - 11 | 0 | 3 | 9 | 6,400 |
| 16 | 05 - 12 | two | 6 | 6 | 22,933 |
| 17 | 05 - 12 | one | 4 | 6 | 13,600 |
| 18 | 05 - 12 | one | 4 | 5 | 13,333 |
| 19 | 05 - 13 | two | two | eleven | 18,933 |
| twenty | 05 - 13 | one | 3 | eleven | 13,600 |
| twenty-one | 05 - 13 | two | 3 | 8 | 19,466 |
| 22 | 05 - 14 | 0 | 4 | 8 | 7,466 |
| 2. 3 | 05 - 14 | one | 8 | 7 | 19,200 |
| 24 | 05 - 14 | two | 7 | 14 | 26,400 |
| 25 | 05 - 15 | one | 3 | 13 | 14,133 |
| 26 | 05 - 15 | one | 5 | 6 | 14,933 |
| 27 | 05 - 15 | 4 | 6 | 8 | 36,800 |
| 28 | 05 - 16 | two | 10 | 9 | 29,066 |
| 29 | 05 - 16 | 3 | 7 | 7 | 31,200 |
| 30 | 05 - 16 | one | 6 | 4 | 15,733 |
- Determination of the number of inspectors and their route.
To determine the number of inspectors and their route, we use the time fund usable by the inspector and the total time it would take to carry out the inspections at the points designated for it.
The working day has 480 minutes, where the time not usable by the inspector must be reduced directly at the inspection site.
The usable time pool was calculated as follows:
FTU = 480 - TDNP + TC
FTU = 480 - 75
FTU = 405 minutes
Where:
FTU: Usable Time Fund.
TDNP: Rest Time and Personal Needs (snack and others).
TC: Daily Counseling time with the workshop management.
- Time required for each inspection.
Inspection Point No. 1: 35 minutes.
Inspection Point No. 2: 30 minutes.
Inspection Point No. 3: 25 minutes.
Inspection Point No. 4: 25 minutes.
Inspection Point No. 5: 25 minutes.
Inspection Point No. 6: 25 minutes.
TOTAL: 165 minutes.
To carry out 3 inspections per day, it will take 495 minutes, that is, 90 minutes above the usable time of an inspector, in addition, the inspection of the batches of raw materials and materials received, as well as that of batches of finished product, so 2 inspectors are needed in the establishment. One of the inspectors will be in charge of the incoming inspection of raw materials and materials and the execution of the inspection of points 4, 5 and 6, while the second inspector would carry out the inspection of the finished product and points1, 2 and 3. The rest of the time will be used in the analysis of the results of the inspections, the preparation of the information, as well as the discussion and solution of the problems detected or others that may arise.The following is the journey of each inspector.
- Tour of the first inspector.
| First | Travel | Second | Travel | Third | Travel | |
| Inspection Points | Begins | Ends | Begins | Ends | Begins | Ends |
| No.1 | 8:50 | 9:25 | 10:50 | 11:25 | 13:40 | 14:15 |
| No. 2 | 9:35 | 10:05 | 12:35 | 13:05 | 14:50 | 15:20 |
| No. 3 | 10:15 | 10:40 | 13:10 | 13:35 | 15:25 | 15:50 |
- Second Inspector Tour
| First | Travel | Second | Travel | Third | Travel | |
| Inspection Points | Begins | Ends | Begins | Ends | Begins | Ends |
| No.4 | 8:35 | 9 o'clock | 10:20 | 10:45 | 13:10 | 13:25 |
| No. 5 | 9:10 | 9:35 | 11:05 | 11:30 | 13:35 | 14:00 |
| No 6 | 9:45 | 10:50 | 12:40 | 13:05 | 14:10 | 14:35 |
Lunch: 11:30 - 12:30
Snack: 8:15 - 8:30 and 14:30 - 14:45
Technical Council: 7:30 - 8:15
CONCLUSIONS
- This work constitutes one of the aspects contemplated by the Statistical Quality Control System that has been developed in this Company. This work has been analyzed with the NMCC Directorate of the Ministry of Light Industry and with the NMCC Department of the Union of Leather and Footwear belonging to said Ministry, having been approved for its implementation in the two fundamental establishments of the company. the work in a period of three months with students from the University of Matanzas "Camilo Cienfuegos", yielding positive results in the final quality of the finished product, as well as in reducing losses in the process by reducing the number of defects in operations.Currently the work is in the implementation phase in all the Company's establishments and in the specific case of Workshop 101 “Samuel Fernández”, its total implementation depends on the approval of the position of another inspector, since the establishment It only has one inspector. We understand that once this work is implemented there will be considerable improvements in the quality of the footwear product, which will positively influence the profitability of the company.which will positively influence the profitability of the company.which will positively influence the profitability of the company.
BIBLIOGRAPHY
- Bowker, Albert H. Engineering Statistics / Albert H Bowker, Gerald J. Lieberman. Englewood: Prentice-Hall Publishing, 1959._Crosby Philip. Let's talk about quality. Ed Mexico 1996 Espinosa Nelson. (1986). Quality Management. Ed ISPJAE, C Havana, Chapter 4. Juran. Joseph. (1993). M. Quality Control Manual. EdGraw-Hill, Spain. Feigenbaum AV Total Quality Control. Ed Cuban
Book Institute 1971
.Galgano, Alberto. (nineteen ninety five). The Seven Tools of Total Quality. Ed Díaz de Santos. Quality control. Ishikawa, Kauro. (1988) What is total quality control? The Japanese Mode. City of The Revolutionary Publishing House. James R. Evans and William Lindsay. (2000) Administration and quality control. Ed Thomson International. Fourth Edition Juran, Joseph M & Gryna Frank, M. (1993) Quality Control Manual. Swear Fourth Edition. Vol. # 2. Mc Graw - HillKothler, P. (1997) Marketing for Hospitality and Tourism. First edition. Prentice Hall. Mexico Montgomery Douglas C. Statistical quality control. Ed CIS, Grupo Editorial Iberoamérica.Part II.Nakhoi and Neves, (1994), The Deming, Baldrige, European Quality awards, Quality Progress, April, USA Standard NC-ISO 8258. Control charts by shewhartRamírez, F. (1989). Organization of economic aspects in the direction of the quality of production in the footwear industry of the Republic of Cuba. Thesis presented as an option to the title of Dr. CT Ukraine. Web page. Quality Discipline. Rodríguez Armando. (1985). Quality Control. Ed ISPJAE, C Havana. Chapter 2. Shainin D. Quality Control at Maynard, Photoreproduced Edition. Engineering and Industrial Organization Manual, 1992. Part III. pp 1002-1006.
CURRICULUM VITAE
Name and surname: Francisco David Ramírez Betancourt
Title: Industrial Engineer
Graduation year: 1977
Title: Dr. in Sciences (1989)
Assistant Professor: 1987
- POST-GRADUATE COURSE RECEIVED:
- National Seminar on Standardization, Metrology and Quality Control (1977 Course) State Inspection Course on Standardization, Metrology and Quality Control (1978 Course) State Inspection Course on Standardization, Metrology and Quality Control (1979 Course) Foundations metrology. Faculty of eng. Industrial (March, 1981) Foundations in Standardization. Faculty of eng. Industrial (March, 1981) Quality Audit Course for the Standardization Teaching Center (February / 1992) National Course for the Quality Audit of the Standardization Teaching Center. (October / 1992) Course NC-ISO-10011-2 “General Provisions for the Audit of Quality Systems. (December, 1992).Administration Course (Direction Diploma) January-2006 Organizational Behavior Course (Direction Diploma) February-2006 Organizational Competency Management Course (Direction Diploma) March-2006 Manager's Personal Work Organization Course (Direction Diploma) April-2006 Strategic Management Course (Direction Diploma) May-2006 Direction Diploma (March 2007)
II.- RECEIVED TRAININGS
- Training on State Inspection in Standardization, Metrology and Quality Control (Course 1980) (Bulgaria)
II.- INVESTIGATIONS CARRIED OUT
- Methodology for the Inspection of the Quality of Crude Sugar in Bulk (1981 to 1982) Minaz Provincial Development of a Material Stimulation System for Quality in the Footwear Industry of the Republic of Cuba (1987 to 1988) Minil Economic Analysis on the Influence of Control of the Quality in the Profitability of the Companies (1987 to 1988) Study on the Losses due to Low Quality in the Agricultural Productions Improvement and Organization of the Process Control in the Footwear Industry (1985 to 1988) Methodology for the Evaluation of the Quality of the Services provided to International Tourism (1990 to 1991) Procedure for payment of suitability in Tourism linked to the results of Quality and Economic Efficiency.(1992 to 1994) Development of an Economic Organizational and Statistical System for the Functioning and Self-financing of Martial Arts in the Country (1991 to 1994). Evaluation of the Effectiveness of the Quality of the Services from the Efficacy and Efficiency. (2005-2007) The costs of quality and its influence on the efficiency and effectiveness of the work of organizations. CIMEX Matanzas and others branch. (2008)
IV.- PUBLICATIONS MADE
- Methodology for the Determination of the Acceptable Quality Level (1981). Normalization Magazine No. 2 (1981). State Inspection in the Territory Critical Assessments and its Development. Standardization Magazine No 3-4 (1983) Methodology for the Design of Bulk Crude Sugar Sampling Plans Standardization Magazine No 4 (1984) Application of Statistical Regulation in the Footwear Process. Normalization Magazine No 2 (1989) Organization of the Economic Aspects of the Footwear Directorate in the Republic of Cuba Scientific Degree Thesis Summary (1989) USSR. Stimulation for quality in Footwear Production Normalization Magazine (1983) Comprehensive Quality Assessment of the services. III International Convention of the University of Matanzas. (2007). CD. of the Event Evaluation,analysis and diagnosis of the effectiveness and efficiency in tourism entities. Event "National Tourism Symposium." (May, 2008)
V.- WORKS PRESENTED AT EVENTS
- III Latin American Congress of Quality Control (1978). Held in Mexico (Querétaro) Participant Title. National System of Normalization. I Scientific Conference of the Camilo Cienfuegos University Center (1983). Speaker. Title. Methodology for the design of Bulk Crude Sugar Sampling Plans. BTJ Provincial Conference. (1984) Speaker. Title. Methodology for the Determination of the Optimal Acceptable Quality Level. Provincial Conference of the BTJ. (1985) Speaker. Title Influence of the control of the Quality in the Profitability of the Company. Scientific contest - Provincial Youth Technician of the BTJ. (1986) Speaker. Title. Design of the Inspection of the Process in the 101 Footwear Workshop. Obtained Prize XII Provincial Scientific-Technical Youth Competition of the BTJ (1988) Speaker. Title.Design of a Material Stimulation System for Quality Obtained Mention. XII Provincial Scientific-Technical Youth Contest of the BTJ (1988) Speaker. Title. Use of statistical methods of quality control in the Footwear process. He was awarded the National Exhibition of the Shapers of the Future. (1988) Speaker. Title. Use of Statistical Methods in the Footwear Production Process. He obtained a Mention in the Third Provincial Meeting of Innovators and Rationalizers. (1988) Speaker. Title. Economic Analysis of the Influence of Quality Control on the Profitability of the Company. Obtained Scientific Conference Held in Kiev Ukraine Institute of Light Industry (1989) Speaker. Title. Design of a Material Stimulation System for Quality Results in the Footwear Industry.Provincial event on quality assurance. (1991). Speaker. Title. Evaluation of the quality of services Provided to International Tourism Obtained Award.
- 2. National Technical Scientific Conference on Quality Assurance (1991). Speaker. Title. Losses due to Low Quality in Agricultural Productions. A project of values with Infants and Adolescents presented linking the family and the community in martial arts in the province of Matanzas, linked to the UNICEF project. Speaker, which was presented at the JURISCUBA 2003 international event and at the III International Conference on Family Law held in Villa Clara in 2004. A project of values with Infants and Adolescents presented linking the family and the community in the arts martials in the province of matanzas, linked to the UNICEF project. Speaker, presented at the III International Conference on Family Law held in Villa Clara in 2004."Comprehensive Evaluation of the Quality of Services". Speaker, he was presented at the IV Scientific Conference of the SUM of Matanzas, where he obtained the category of relevant, being selected for the FORUM. (May, 2007) "Comprehensive Evaluation of the Quality of Services" XVI Municipal Forum of Science and Technology. Speaker. (Obtained award) (November, 2007) Comprehensive Evaluation of the Quality of services, was presented at the III International Convention of the University of Matanzas. Ciemprestur event. Speaker. (June, 2007). Evaluation, analysis and diagnosis of the effectiveness and efficiency in tourism entities. Event "National Tourism Symposium." Speaker. (May, 2008) Evaluation of the level of satisfaction of students and teachers with the study guides. Speaker. (April. 2008) Preparation of the subject Quality of services. Speaker.V Scientific Methodological Conference of the University. (June, 2008).
VI.- LANGUAGES
Graduated from language school. Russian 1979.
Second level of English
VII.- TRAINING AND POST-GRADUATE COURSES TAUGHT
- Course on Fundamentals of Quality Control (Course 1978-1979) Postgraduate degree on quality control University Center of Matanzas. 20 hrs. (Course 1980-1981). Conference on quality control for Business Directors. 1985 Post-grade quality reorientation at ISAICC. 40 hrs. 1986-1987 academic year Quality Control. Production Management Master. University of Matanzas 2002. Course of management techniques to the department of records of the provincial administration of justice (management by objectives).Module of Quality Management in a Diploma in Management at CITMA (2006) Module of Quality Management in a Diploma of Direction of the SUM Matanzas. (2007) Module of Quality of the Management of the Master of Administration.
