Newbie looking at 6040 (China CNC) for polypropylene 15mm sheet

[spluppit]

Re: Finishing and part quality.

First of all please do not think i am purposely going out of my way to make you feel bad or I'm being difficult. You have come a long way since the beginning of your post to actually making parts from knowing very little. You should be proud of that and well done. I have tried to gently explain you are a world away still. It really is not as simple as people think at times as buying a machine and making parts. I did a 5 year Toolmaking apprenticeship and 4 years at college and before that i was still on the shop floor for a year before they were satisfied to put me through the apprenticeship etc. Then you are still not considered accomplished that takes another 5 to 10 years. On top of that i have always been in machine shops and workshops since i was a child and had a natural aptitude for the Job. I hope you can try to see this as more a education rather than criticism.

I do not agree that your parts are fine. Without seeing any images of your finished parts, I said you were using the wrong material and the evidence is those images you posted. I appreciate images can be a little deceiving online but i have seen and taken enough to hopefully know what im looking at. Yes your parts are anodised but that is a very broad use of the term, in the fact they have been dumped in a sulfuric tank with some current and then dyed. But that's as far as it goes. The finish is flat and and one one those images shows very blotchy uneven finish and a lot of surface marks. Cosmetics is as important as the function of the item in today's word if its a product people will see and use. (more so if they are paying decent money for it) I did read about you tumbling or vibratory finishing these parts. There are a ton of variables with finishing which i cant go into here but I feel its the wrong move if you understand the anodising process. (Don't slate me for saying this guys, as i said i cant go into full detail) A quick debur if necessary fine but.. the rest hmmmm. By rights parts like this you anodise off the machine. This is 2017.

Also finding a good anodiser is very hard indeed. I know from loosing thousands of pound to idiot ones out there in past years. With this in mind there could be an element of error from the anodiser as i said good ones are very hard to find. I cant tell categorically because I'm not there to see in the flesh. If your anodiser has not mentioned about the quality of the finish on the part or his anodising don't use him is my advice.

You have taken the path of least resistance (on advice granted) to get to your end goal, sadly it does not work like that in manufacturing. I mean this is the politest way but i get the feeling some of the problems is you don't actually know what you are looking at yourself to decide if its acceptable or not.

The result of the part is only as good as the work gone into it.

These images taken last night are literally bits laying about the workshop and these are scrap for various reasons, finishing being one of them. A lot of these parts are very old indeed most of the anodised parts are anything from a year old to up to 25 years old or so. The bare Aluminum parts are straight off the machine, you can anodise straight off this, no finishing and you will get a beautiful satin jet black uniform finish, of course requiring an anodiser who is not a banana eating Orangutan. I could not find a lot of black anodising laying about, but there are few bits and i'm sure you can see the difference.

I will reply to your other post to me in more detail when i get a chance. Also to mention about the cost you were given of £60.00. If you read my pm you will see i explained that you are making the part expensive, the models are not compete for a start, plus you have now altered one. I said about having a chat on the phone to reduce this cost because i expect typically, the tight rads that are probably not necessary plus many other things that can help. This is why you got a very inflated quote. They looked at the part and glazed over, exactly as i did but i offered help, to help you reduce the cost. They should be no where near the price you have been quoted with a little work to make it easier on the manufacturing. You would pick the parts up tapped holes as well.

Its a package deal, knowing how to machine to design economically to machine economically. You cant learn that in 10 months or so.