Tolerances

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“We have been working with you since more than 10 years. During this period your quality & delivery performance found is very good. Even when we arranged a supplier meet in 2012 we awarded you as a best supplier of the year in Bought out item category. Whenever we had any new developments your support was perfect. Overall your performance was very good & we hope the same in future too, We wish you all the best for your business growth.”
Sidel India Pvt. Ltd.
“We are working with Harkesh Rubber since 3 years. Our initial development of few seals for one of the important project developed and supplied by them as per the schedule. We found the quality and commitment for overall business is good. The response and technical support for our need is fair and on-time. Overall the services and co-operation found to be satisfactory. We wish the young and energetic Harkesh Rubber team a very best in all the future endeavours.”
Festo India Pvt Ltd.
“Harkesh Rubber Industries has been our co-partner for the supply of the rubber and its allied products from past 2 years which we used in our daily final product made for Indian Railways. We find the quality of product supplied by them in superior quality which lowest lead time. Overall the services and cooperation found out to be satisfactory in all key areas.”
Crompton Greaves Limited
“Harkesh Rubber Industries has been our co-partner for the supply of the rubber and its allied products from past 2 years which we used in our daily final product made for Indian Railways. We find the quality of product supplied by them in superior quality which lowest lead time. Overall the services and cooperation found out to be satisfactory in all key areas.”
Crompton Greaves Limited
“In all honesty I have to say that for us it's really a pleasure to do business with you now already more than 5 years. In the whole time you had never let us down, your delivery performance is nearly perfect, the service which we get is quicker than quick. The product quality has been never a problem and when we had an issue you help us always to solve it. This reliability is where we trust in and what makes our decision to work with you also in the future very easy.”
ARCA Regler GMBH
“Dear Harkesh Rubber Team, We have been working with you since last 6 years. During this period your Quality, Delivery and Performance found very good and consistent. During the development of new products specially FKM/FPM gaskets, we had very good technical support by your team, and we hope in future it will remain same. We wish you all the best for your business growth. Thanking you,”
Georg Fischer Piping Systems Pvt. Ltd.

Thermally molded elastomers are dependent on the following factors:

  • Compound variation
  • Mold tolerance
  • Shrinkage
  • Mold registration
  • Temperature
  • Cure time

Shrinkage could arise on elastomers depending on the following factors:

  • Tool design
  • Shape
  • Material
  • Molding

To account for the variables that are included in the manufacturing process, it is vital to define tolerances. This can help achieve the required level of precision and quality.

ISO 3302-1

1) ISO 3302-1 states the various classes of tolerances and their values for molded, extruded, and solid rubber products. The applicable test methods required for complying with ISO 3302-1 are also defined.

2) Note that the tolerances are mainly intended for vulcanized rubbers. However, they may be suitable for thermoplastic rubbers as well.

Measurement

3) Four tolerance classes ranging from M1 to M4 are defined. Based on the press direction of the mold, differences are calculated between the mold dimensions and the two-component adhesion system measurements of the mold closure.

Tolerance Classes

1) M1 (Precision Moldings) – Requires precision molds, close mix controls, and fewer cavities per mold. Measuring devices such as optical comparators may be needed to reduce distortion of the compound.

2) M2 (High-Quality Moldings) – Involves most of the close control needed for M1 class.

3) M3 (Good-Quality Moldings)

4) M4 (Non-Critical Dimensional Control Moldings)

Dimensional Tolerances

The dimensional tolerances defined in ISO 3302 could be wider than the ones used in certain engineering practices. Listed below are the following considerations:

1) When rubbers are cooled after molding, they will show some shrinkage. The amount of shrinkage depends on the mix used and elastomer type. However, it can vary from batch to batch.

2) Non-rubber fragments that are bonded to elastomers could affect the practicable tolerances and shrinkage.

3) Molds can be manufactured in different ways depending on the accuracy demanded and the product type. Also, if the degree of accuracy is greater, the molds and their maintenance will be more expensive.

4) Products that have a wide sectional variation will require more care in applying the standard tolerances.

5) During mold removal, if the rubber products are distorted, the dimensions may be affected, and a special allowance may be required.

Geometrical Tolerances

ISO 3302 defines geometrical tolerances for molded and extruded elastomer products, including the ones with metal inserts:

  • Parallelism Tolerance
  • Positional Tolerance
  • Coaxial Tolerance
  • Flatness Tolerance
  • Perpendicularity Tolerance

Thermally molded elastomers are dependent on the following factors:

  • Compound variation
  • Mold tolerance
  • Shrinkage
  • Mold registration
  • Temperature
  • Cure time

Shrinkage could arise on elastomers depending on the following factors:

  • Tool design
  • Shape
  • Material
  • Molding

To account for the variables that are included in the manufacturing process, it is vital to define tolerances. This can help achieve the required level of precision and quality.

ISO 3302-1

1) ISO 3302-1 states the various classes of tolerances and their values for molded, extruded, and solid rubber products. The applicable test methods required for complying with ISO 3302-1 are also defined.

2) Note that the tolerances are mainly intended for vulcanized rubbers. However, they may be suitable for thermoplastic rubbers as well.

Measurement

3) Four tolerance classes ranging from M1 to M4 are defined. Based on the press direction of the mold, differences are calculated between the mold dimensions and the two-component adhesion system measurements of the mold closure.

Tolerance Classes

1) M1 (Precision Moldings) – Requires precision molds, close mix controls, and fewer cavities per mold. Measuring devices such as optical comparators may be needed to reduce distortion of the compound.

2) M2 (High-Quality Moldings) – Involves most of the close control needed for M1 class.

3) M3 (Good-Quality Moldings)

4) M4 (Non-Critical Dimensional Control Moldings)

Dimensional Tolerances

The dimensional tolerances defined in ISO 3302 could be wider than the ones used in certain engineering practices. Listed below are the following considerations:

1) When rubbers are cooled after molding, they will show some shrinkage. The amount of shrinkage depends on the mix used and elastomer type. However, it can vary from batch to batch.

2) Non-rubber fragments that are bonded to elastomers could affect the practicable tolerances and shrinkage.

3) Molds can be manufactured in different ways depending on the accuracy demanded and the product type. Also, if the degree of accuracy is greater, the molds and their maintenance will be more expensive.

4) Products that have a wide sectional variation will require more care in applying the standard tolerances.

5) During mold removal, if the rubber products are distorted, the dimensions may be affected, and a special allowance may be required.

Geometrical Tolerances

ISO 3302 defines geometrical tolerances for molded and extruded elastomer products, including the ones with metal inserts:

  • Parallelism Tolerance
  • Positional Tolerance
  • Coaxial Tolerance
  • Flatness Tolerance
  • Perpendicularity Tolerance

NEED HELP?

Speak with a human to filling out a form? call corporate office and we will connect you with a team member who can help.

“We have been working with you since more than 10 years. During this period your quality & delivery performance found is very good. Even when we arranged a supplier meet in 2012 we awarded you as a best supplier of the year in Bought out item category. Whenever we had any new developments your support was perfect. Overall your performance was very good & we hope the same in future too, We wish you all the best for your business growth.”
Sidel India Pvt. Ltd.
“We are working with Harkesh Rubber since 3 years. Our initial development of few seals for one of the important project developed and supplied by them as per the schedule. We found the quality and commitment for overall business is good. The response and technical support for our need is fair and on-time. Overall the services and co-operation found to be satisfactory. We wish the young and energetic Harkesh Rubber team a very best in all the future endeavours.”
Festo India Pvt Ltd.
“Harkesh Rubber Industries has been our co-partner for the supply of the rubber and its allied products from past 2 years which we used in our daily final product made for Indian Railways. We find the quality of product supplied by them in superior quality which lowest lead time. Overall the services and cooperation found out to be satisfactory in all key areas.”
Crompton Greaves Limited
“Harkesh Rubber Industries has been our co-partner for the supply of the rubber and its allied products from past 2 years which we used in our daily final product made for Indian Railways. We find the quality of product supplied by them in superior quality which lowest lead time. Overall the services and cooperation found out to be satisfactory in all key areas.”
Crompton Greaves Limited
“In all honesty I have to say that for us it's really a pleasure to do business with you now already more than 5 years. In the whole time you had never let us down, your delivery performance is nearly perfect, the service which we get is quicker than quick. The product quality has been never a problem and when we had an issue you help us always to solve it. This reliability is where we trust in and what makes our decision to work with you also in the future very easy.”
ARCA Regler GMBH
“Dear Harkesh Rubber Team, We have been working with you since last 6 years. During this period your Quality, Delivery and Performance found very good and consistent. During the development of new products specially FKM/FPM gaskets, we had very good technical support by your team, and we hope in future it will remain same. We wish you all the best for your business growth. Thanking you,”
Georg Fischer Piping Systems Pvt. Ltd.
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