Totally agree with other replies, having a bad relationship between R&D and Quality Department could lead to work deficiency and further delays as well as many other barriers that would hinder the workflow in its right and proper way.
One way to overcome disagreements between these two departments is to limit the direct contact between R&D’s and quality people as engineers and scientists would think in a completely different way, which could lead to a misunderstanding by the quality department. A training course for both department’s employees would be a good idea to let each understand how to deal with the other side and to understand the exact role for each side so that none would do the work for the other side. Clear and well-defined rules and outlines for the company goals and duties for each department that could not be exceeded by any employer also would lower the chance of conflicts.
Setting the company environment to work as a group would also let everyone in all departments work together and have a better approach to deal with problems.