Comments on: Possibilities of Why a Polycarbonate (PC) Part Is Cracking http://www.matrixtooling.com/blog/possibilities-of-why-a-polycarbonate-pc-part-is-cracking/ A compilation of manufacturing tips covering plastic mold design, build, injection molding and the inspection of finished plastic products as well as often overlooked manufacturing issues from a small business perspective. Contributed by various employees of Matrix Tooling, Inc. & Matrix Plastic Products. Mon, 29 Mar 2010 01:47:40 +0000 http://wordpress.org/?v=2.9.2 hourly 1 By: Daneplast http://www.matrixtooling.com/blog/possibilities-of-why-a-polycarbonate-pc-part-is-cracking/comment-page-1/#comment-7617 Daneplast Mon, 09 Nov 2009 14:40:48 +0000 http://www.matrixtooling.com/blog/?p=142#comment-7617 hand lotion causing cracking.. absolutely crazy! but that's how precise this line of work has to be. hand lotion causing cracking.. absolutely crazy! but that’s how precise this line of work has to be.

]]> By: Express Engineering http://www.matrixtooling.com/blog/possibilities-of-why-a-polycarbonate-pc-part-is-cracking/comment-page-1/#comment-7615 Express Engineering Mon, 09 Nov 2009 13:42:23 +0000 http://www.matrixtooling.com/blog/?p=142#comment-7615 great post, BrentB, I was looking for this exact information! great post, BrentB, I was looking for this exact information!

]]> By: brentb http://www.matrixtooling.com/blog/possibilities-of-why-a-polycarbonate-pc-part-is-cracking/comment-page-1/#comment-6620 brentb Mon, 26 Oct 2009 19:44:34 +0000 http://www.matrixtooling.com/blog/?p=142#comment-6620 Polycarbonate is prone to suffer from black specks. This is especially evident in white and clear resins. Of course a scrupulous cleaning program prior to molding is important. A purging program with a product such as DynaPurge M is usually sufficient. Contact www.dynapurge.com for a free sample and instructional video. In extreme cases, the screw must be pulled and screw and barrel physically cleaned. Many molders of white and clear PC, who have dedicated machines for this resin, will purge the machine almost empty, but leave the PC in the barrel and lower or "bank "the barrel temps at about 350°F. They leave them banked, even over the weekend. This minimizes black specks on startup. The specks can not only come from resin that has been run prior to, but from degraded PC. The purging/cleaning removes the prior resins, the banking minimizes specking from the degraded production PC. Specking is common and afflicts most PC molders at one time or another. Hope this helps. Brent Borgerson Matrix Tooling/Matrix Plastic Products Polycarbonate is prone to suffer from black specks. This is especially evident in white and clear resins. Of course a scrupulous cleaning program prior to molding is important.

A purging program with a product such as DynaPurge M is usually sufficient. Contact http://www.dynapurge.com for a free sample and instructional video.

In extreme cases, the screw must be pulled and screw and barrel physically cleaned. Many molders of white and clear PC, who have dedicated machines for this resin, will purge the machine almost empty, but leave the PC in the barrel and lower or “bank “the barrel temps at about 350°F. They leave them banked, even over the weekend. This minimizes black specks on startup. The specks can not only come from resin that has been run prior to, but from degraded PC. The purging/cleaning removes the prior resins, the banking minimizes specking from the degraded production PC. Specking is common and afflicts most PC molders at one time or another.

Hope this helps.

Brent Borgerson
Matrix Tooling/Matrix Plastic Products

]]> By: mitesh http://www.matrixtooling.com/blog/possibilities-of-why-a-polycarbonate-pc-part-is-cracking/comment-page-1/#comment-6321 mitesh Thu, 22 Oct 2009 03:10:44 +0000 http://www.matrixtooling.com/blog/?p=142#comment-6321 Sir, Thanks for your valuable information on PC part cracking. We are a mould mfg and molder for the engineering plastics. We do mainly molds for the modular switch industries. We mainly deal with the PC.(specific white Lexan PC ) My question is what is the reason of black spot generating during molding of polycarbonate. Please explian in details. Mitesh. Sir,

Thanks for your valuable information on PC part cracking.

We are a mould mfg and molder for the engineering plastics. We do mainly molds for the modular switch industries.

We mainly deal with the PC.(specific white Lexan PC )

My question is what is the reason of black spot generating during molding of polycarbonate.

Please explian in details.

Mitesh.

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