About Us

Since the doors opened in 1969, Roncelli Plastics’ mission has been committed to deliver critical plastic parts for the most demanding applications. We are determined to provide exceptional customer service alongside precision production of plastic components in critical industries. Over the years Roncelli Plastics has stayed on pace with our trusted partners, providing support for organizations ranging from fortune 100 corporations, to early stage hyper growth startups.

A Leading Plastics Manufacturer For Over 50 Years

Committed to investing in the most efficient manufacturing technologies and outstanding people, Roncelli Plastics empowers an atmosphere of accountability, reliability, and dependability, where open communication and teamwork translates to customer success. Roncelli Plastics’ diverse team of experienced engineers, machinists, inspectors, supervisors, and managers are dedicated to the pursuit of Roncelli Plastics’ core values:

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Safety First, Always

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Great Origination, Seamless Handoffs and Zero Defects

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Accountability, Responsibility and Extreme Ownership

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Continuous Improvement

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Respectful, Professional, Friendly, and Open Door Culture

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Excellent Service Through Integrity and Open and Honest Communication

Company Culture

Roncelli Plastics seeks to attract, retain, and reward the very brightest minds in the industry by providing a safe, friendly, and supportive work environment where management not only recognizes employees who exceed expectations, but rewards them for their commitment to excellence. For 50 years Roncelli Plastics has invested in its employees’ development to improve their individual contributions and provide opportunities for career advancement.

Education Development

Roncelli Plastics supports the continued education of all employees. The company offers paid courses and partial reimbursement for job related classes.

Company Events

Company-wide quarterly reviews with catered lunch. Holiday parties and gift-giving including Thanksgiving Turkey or Ham giveaways.

Customer Quality Awards

Roncelli Plastics has been honored by various customers for our commitment to quality. These recognitions include:

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Boeing Preferred Supplier Inspection Delegation

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Boeing Small Business of the Year

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Boeing Performance Excellence Award

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Collins Technologies - DSQR (Delegated Source Quality Rep)

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Emerson Rosemount Dock to Stock Certified

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Honeywell Self Release Supplier

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Raytheon Preferred Supplier

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UTC Interiors & Propulsion Dock to Stock Certified

Corporate Philanthropy

It has been a tradition at Roncelli Plastics for a couple of decades to support organizations making a difference in the communities where we we work and live. Here are just a few of those partnerships.

Our employee giving program supports Children’s Hospital Los Angeles, a top ranked pediatric healthcare facility serving children locally and abroad.

Boys & Girls Clubs of the Foothills; provides educational empowerment classes, career development and mentor ship. We’re currently supporting their STEM education programs.

Villa Esperanza, an organization serves intellectually/ developmentally disabled individuals and their families.

Five Acres, provides health and well being programs to children in the Los Angeles area and surrounding communities.

Visit Us

We’ve always believed people partner with people not with a company. Come take a tour of our facility, and meet our staff. To schedule your tour or phone call with us select the contact us.

In addition to our headquarters, located in Monrovia, CA, our sales staff can be accessed at any one of these locations:
San Jose, CA
Dallas, TX
Orlando, FL
Boston, MA