Problems Faced by CNC Machines End Users at

Jour of Adv Research in Dynamical & Control Systems, 12-Special Issue, August 2017

Problems Faced by CNC Machines End Users at Coimbatore District R. Ganesh Kumar, Ph.D. Research Scholar, Management, Karpagam Academy of Higher Education, Coimbatore. R. Velmurugan, Associate Professor, Commerce, Karpagam Academy of Higher Education, Coimbatore.

Abstract--- End users of CNC machines will feel discomfort and may spread negative feedback and information about the problems to their friends and relatives and also to the public, if any sort of problem is noticed at CNC machines. This will seriously impair the turnover of the CNC machines. Further, the negative feedback may also ruin the brand image of the CNC machine manufacturers. In order to improve the market share and also for retaining the existing market or achieving the targeted sales of CNC machines, it is essential to study the customer's problem on using CNC machines. Thus, in this study, an attempt has been made to ascertain the major problems faced by CNC machine end users at Coimbatore district. By employing purposive sampling technique, primary data have been collected from 150 CNC machine end users. The collected data have been analyzed by the employing factor analysis. The result of the study discloses that coolant less flow, difficult of chip disposal without chip conveyor less guide way wiper life are the frequent problems faced by the CNC machine end users. Keywords--- CNC Machines, Coolant Problem, End User’s Problem.

I.

Introduction

CNC machine means “Computer Numerical Control” machines. In CNC machines, functions and motions are fully automatic which are controlled by the Programme (set of instructions). Hence, for operating the CNC machines, frequent supervision and manual intervention is not required. In CNC machine, there is two major parts (Hardware part and Software part) in operation. Hardware part consists Electrical motors, motor drives etc., and software part consists Electrical Logic and CNC programme. Purpose of the CNC machine is either metal removing or metal forming process. CNC machines are being used for metal cutting process and non metal cutting process. CNC machines are also being used for Laser cutting process, Electric discharge machining and other special process. CNC machines in India offers employment opportunities directly and indirectly to two lakh employees. Total Turnover of Indian CNC manufacturers are $690.80 per year. Turnover will change every year depending upon the Indian Industry’s need and usage. CNC industry contributing major role towards the growth of Indian Industry by providing high quality with best price CNC machines as per the Indian industry’s requirements and also reducing the need of CNC machine imports from foreign countries (Preventing our Indian money which goes to abroad. Ultimately it results our Country’s growth). Coolant less flow or low pressure at tool tip, Difficult of chip disposal without chip conveyor, Less Guide way wiper life, Machine idle due to spindle alarm/CNC system problem, Hydraulic oil temperature is high, Machine spares cost is high, Delay in supply of spares (due to shortage at “CNC” machine manufacturing place) are the common problems faced by CNC users. Rectifying the problems at CNC machine user place are essential for achieving the customer satisfaction, getting repeated orders from the same customer and also for running the CNC manufacturing and selling business.

II.

Review of Literature

Multimcam (2017) in their study stated that burning of material on the outside of the edge, chatter and overheating are the common problems faced by CNC end users. AMMC (2016) in their study pointed out that the improper tools settings and improper programming are the major problems committed by users of CNC machines. A study by machinetoolhelp.com observes that the Tool changer ATC problems, Servo & Drive alarms, Pulse coder alarms, Way Lube problem, Low voltage problems at device, Zero Return problems, Power supply problems, Axis brake, Door interlock circuit problems, Chuck will not clamp/unclamp, Relay board problems and Hydraulic problem are the common problems faced by the end users. Anand (2017) in his article mentioned that improper tool settings, improper maintenance and improper programming of CNC machines lead to break downs in CNC machines. Nazir B. Tamboli (2016) in his article pointed out improper setting, improper maintenance and improper programming lead to failure of CNC machines. Joe Bennick and John Frauenhoffer (2006) in their study states that cutting fluid problems, which reduces the quality of output in CNC machines, is major problem that prevail at CNC

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machines. Hinsu Jindal, Rakesh Kumar and Kartik D. Kothari (2014) in their study ascertained the axis slips downwards due to inertia and gravitational force in Vertical axis CNC machines and motion errors of the rotary axes in five-axis CNC machine tools are the common problems prevail at CNC machines. Sushrut S. Pavanaskar (2014) in his study observes that 5-axis tool path planning problem is the common problem that prevail at 5 axis CNC machines. Ghetiya and Saurin Panchal (2014) in their study ascertained that the problem of Ovality deteriorate the quality of output of CNC machines. Major of the studies covers only few specific problems on CNC machines. Not much study has been carried on addressing the various problems faced by CNC machine end users. Thus, the present study covers numerous problems that prevail at CNC machines from end users’ point of view.

III.

Statement of the Problem

When the problem found in the CNC machine, customer will feel discomfort and may spread negative feedback and information about the problems to their friends and relatives and also to the public. This will seriously affect the turnover of the CNC machines. This may also spoil the brand image of the particular product and also spoil the name of the CNC machine manufacturer. In order to improve the market share and also for retaining the existing market/for achieving the targeted sales of CNC machine, it is essential to study the customer's problem on using CNC machine. Studying the customer's problems and solving the same will result in improving (more) the life of the CNC machines. Further, Customers will place repeated orders to the same brand (Model) of the CNC machines when they did not face any complaint in the particular product. Thus, in order to increase the turnover and Sales of the CNC machines, it is essential to study the customer's problem on using CNC machine. Hence, in this study an earnest attempt has been made to ascertain the problems faced by the customers on using CNC machine and to suggest suitable measures to enhance customer’s satisfaction. Objective To identify the problems faced by CNC end users.

IV.

Methodology

Data Data required for the study have been collected by employing Questionnaire method. Area of Study The present study is confined to end users situated at Coimbatore district. Sample Design By adopting purposive sampling method data collected from 150 end users of CNC Machines. Framework of Analysis The collected data have been analyzed by making use of Factor analysis. Analysis and Interpretation Table 1: KMO and Bartlett's Test Kaiser-Meyer-Olkin Measure of Sampling Adequacy. Bartlett's Test of Sphericity

Approx. Chi-Square

.720 1444.000

df

136

Sig.

.000

To ascertain vital problems faced by end users on CNC machines factor analysis is employed. The following table illustrates the imperative problems faced by end users. In order to ascertain whether the data is proper for employing factor analysis, Kaiser-Meyer-Olkin (KMO) and Bartlett’s Test of Sphericity have been employed. The result of KMO and Bartlett’s Test is found greater than 0.70. Hence, the collected data is fit for employing the factor analysis. Further, the large values of Bartlett’s sphercity test (1444.00, df: 136 Sig=0.000) and KMO statistics (0.720) indicated the appropriateness of factor analysis.

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Table 2: Problems Faced by CNC End Users Particulars Coolant Leakage Cooalnt less flow or low pressure at tool tip Poor Chip Management Less Guide way wiper life Difficult of chip disposal without chip conveyor Spindle belt slippage due to coolant fumes entry at spindle belt area Machine idle due spindle alarm / CNC system problem Operator discomfort due to coolant fumes generation during machining Machine spares cost is high Delay in supply of spares (due to shortage at "CNC" machine manufacturing place) Hydraulic oil temperature is high Hydraulic oil leakage (at few areas) Only trained operator can do “CNC” programme Only trained person can do the maintenance work in “CNC” machine Few spare parts are not available in the open market (it is only available at "CNC" machine manufactures) Some times customer dissatisfaction due to delay in technical support from the “CNC” machine manufacturers. Break down maintenance cost is high Eigen Values % of Variance Cumulative % of Variance

1 0.697 0.780 0.669 0.757 0.771 0.503 0.365 0.381 0.286 0.408 -0.037 0.233 -0.337 -0.396

2 0.241 0.334 0.513 0.261 0.018 0.538 0.196 0.389 0.260 -0.111 0.900 0.816 -0.321 -0.435

3 0.129 0.197 0.143 -0.073 0.304 -0.168 0.011 0.110 0.762 0.707 0.060 0.065 0.008 -0.025

4 0.040 -0.064 0.068 -0.131 -0.021 0.050 0.594 0.341 0.117 -0.084 0.040 -0.227 0.763 0.527

-0.129

-0.048

0.782

-0.038

0.682

-0.134

0.190

0.095

0.319 6.093 35.838 35.838

0.175 2.351 13.830 49.668

0.581 1.442 8.485 58.153

0.475 1.349 7.935 66.088

Four factors are identified by locating Eigen values greater than unity. Problems which have a component loading of 0.7 and above are said to be vital problems faced by end users. From the rotated component matrix, it can be seen that “Coolant less flow or low pressure at tool tip”, “Difficult of chip disposal without chip conveyor” and “Less Guide way wiper life”. In the second factor, “Hydraulic oil temperature is high” and “Hydraulic oil leakage” are found to be significant. In the third factor, “Few spare parts are not available in the open market (it is only available at "CNC" machine manufactures)”, “Machine spares cost is high” and “Delay in supply of spares (due to shortage at "CNC" machine manufacturing place)” are found to be significant. In the Fourth factor, “Only trained operator can do the “CNC” programmes” which are found to be significant. Factor one contributes to a tune of 35.838 per cent towards the CNC machine end users problems. The other factor contributes namely, 13.830, 8.485 and 7.935 towards the CNC machine end users problem. The total cumulative percentage of problem contributed by these four factors on the end users is 66.088 per cent.

V.

Suggestions The following suggestions are offered to contain problems faced by Industrial users. •

• • • •

•

To contain Coolant problem, (a) Correct Volume of the coolant to be filled inside the machine coolant tank, (b) As per the customer usage and application requirement, correct capacity and model no. coolant pump must be selected and fitted in the machine, (c) Coolant leakage at hoses, end fittings must be checked and arrested at machine assembly and testing area. Chip conveyor and chip bin are to be supplied to customer place along with the CNC machines for better chip disposal. End user (customer) should maintain the machine with clean and also periodic cleaning the machine’s cutting area and chips collecting area is essential for maintaining the (achieving) Guide way wiper life. Hydraulic oil coolers are to be used in the CNC machine for reducing the high temperature of hydraulic oil and also for maintaining the correct recommended oil temperature. This results, elimination of machine break down. Hydraulic oil leakage must be arrested immediately when it is noticed in the CNC machine. Periodic maintenance of CNC machine will prevent hydraulic Oil leakage. Oil seals must be checked and replaced periodically for eliminating oil leakage problem. Hydraulic connector, hoses and end fittings to be checked periodically and defective parts to be immediately replaced. For the benefit of the customer, CNC machine manufacture should keep the spare parts ready for long term for eliminating the machine break down time at customer place for the need for the spare parts. For the benefit of the customer and also for eliminating the duplicate (Poor quality spare parts) in the open market, manufacturer will sell the spares directly to the customer (not to outside shop keeper)

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•

• • •

VI.

Increasing the production volume of Spare parts will reduce the spares cost. For the benefit of the customer, CNC machine manufacture should keep the spare parts ready for long term for eliminating the machine break down time at customer place for the need for the spare parts. CNC machine manufacturer has to manufacture and procure more quantity of the spare parts for reducing the spare parts cost. CNC machine manufacturer has to properly plan and maintain the required spares store stock for eliminating delay in supply of spares. In addition to the above required quantity of the spare parts to be produced and procured for eliminating delay in supply of spares. Training is essential for generating the CNC programme and also for operating CNC machines. However, CNC System (Electronic parts) manufacture has to develop CNC machine user friendly interactive software for eliminating the dependency of the trained operator. CNC machine must be maintained properly. Preventive maintenance to be done for eliminating this problem. CNC System (Electronic parts) manufacturer has to solve this problem during manufacturing and testing of Electronic parts. CNC Machine manufacturer also has to thoroughly inspect and test the machine before dispatching to the customer place.

Conclusion

In the CNC machine, the generation of problems are mainly due to the poor maintenance of the CNC machines. For eliminating the problems, CNC machine end user has to thoroughly study and follow the instructions available in the machine manual which is being supplied to the customers along with each and every CNC machines. For eliminating major break down of CNC machines, it is essential to completely solve the problems when it is small. For example, hydraulic oil leakage must be arrested when the leakage quantity is a single drop. When the hydraulic oil leakage is ignored by the end user, major accident could be happened which results injury to the machine operator and also damage to the parts of the CNC machine. Coolant less flow or low pressure at tool tip problem may be eliminated by arresting the coolant leakage and replacing the defective parts like Coolant hoses and coolant connectors. When this coolant problem is ignored by the end user, results in damaging of costlier cutting tool, cutting inserts and producing the poor quality of the components, which results rejections and major lose to the CNC users. Less Guide way wiper life problem could be eliminated by maintaining the machine with clean with proper periodic maintenance. Failure of guide way wiper will result the leakage of coolant and rust formation to the accurate parts of the CNC machine which results loss to the end user.

VII.

Scope for Further Research

Customer's problem study shall be extended to many other industries and there is a wide Scope for Further Research which shall be conducted in the other types of industry like textile machine manufacturing, food products manufacturing industry, Consumer products manufacturing industry, Automobile industry, Cutting tools manufacturing industry, Electrical components manufacturing industry, Cutting Oil manufacturing industry, Electronic components manufacturing industry, Mobile phone manufacturing industry etc.,

References [1] [2] [3] [4] [5] [6] [7] [8] [9]

Multimcam (2017), https://www.multicam.com/4-common-cnc-machining-problems/ AMMC (2016), http://ammc.com/common-cnc-machine-problems/ Anand (2017), https://www.quora.com/What-are-the-problems-in-CNC-machines Nazir B. Tamboli (2016), http://www.tamboliengg.com/cnc-turned-components/most-commonly-facedcnc-machine-problems/ Joe Bennick and John Frauenhoffer (2006), http://www.neucodistributors.com/files/Most_Common_Cutting Fluid_Problems.pdf Hinsu Jindal, Rakesh Kumar and Kartik D. Kothari. Modern Techniques in CNC Machines–A Review. International Journal of Advance Engineering and Research Development 1 (6) (2014) 1-4. Sushrut S. Pavanaskar. Improving Energy Efficiency in CNC Machining. Ph.D. Thesis, University of California (2014). Ghetiya, N.D. Some Studies on Reduction of Ovality in Turned Component-Case study. Nirma University Journal of Engineering and Technology 3 (1) (2014) 39-46. http://www.machinetoolhelp.com/Troubleshooting/Machine_tool_troubleshooting.html

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