I can't tell you how many times I have checked out residue problems the "cause machine malfunctions" only to find the chuck or what ever filled with very small chips blown in with an air gun just "cleaning up". Low pressure high volume fluid works much better and it is cheaper also.
Look at he...
Make dam sure that the fluids used are compatible with the materials involve. Depending on the end use of material to be ground.
Over the years I have been bitten by changing the dialectic of the material, incompatible residues left on the surfaces, moisture up take in the material etc. etc...
You need to look at fluid selection very carefully!
The first question you need to look at is the question of Co (cobalt) leach- this is when the fluid solublizes the Co binder (the most common WC -tungsten carbide- binder. leaching the Co out will cause the WC to have reduced shock...
It also looks like you may be recirculating "swarf" and than you may be pressure welding it to the work piece -- this may be the cause of the "fish tails"
I also agree that the "rough" finish is nothing more than regular grinding problems eg too course a wheel, improper coolant flow (volume...
A large percentage of the energy necessary to "drive" a tip comes from the flank of the tap rubbing on the freshly cut threads thus the deeper you go the bigger the problem. Thus applying coolant or oil can make a big difference. when selecting the fluid you are looking for a fluid that has the...
Also you will want to make sure that the mixing in your lab batch is the same as you production mixers -- eg energy input paddle and vessel design etc. -- scale up is always a bixx
From a coolant point of view any thing with polar surfactants, oil, or chlorine (any halogen) can introduce stress into acrylics (they can will deplete the plasticizers in the part).
A.R. "Andy" Nelson
Engineering Consultant
anelson@arnengineering.com
There are several possibilities-
1- that your fluid is so contaminated with tramp oil that your refractometer is over whelmed and can not read the fluid. A good quality digital refractometer will/may solve this problem.
2- If you are using an emulation (soluble oil) type fluid the emulsion may...
I suggest that you get a holed of the company that manufactured your saw and or the Lenox saw technician and see what is available off the shelf -- it is often much more cost effective to buy proven technology than to reinvent the wheel
Are your rejects randomly distributed through out the run or do they come in batches?
If they occur in batches check your wheel size - as you approach stub size your SFPM --you may be getting so slow that your wheel is acting too hard.
Alternatively if you are grinding the shoulder take a look...
You state that you only have this problem on the machined surfaces -- if it was only the fluid you would expect it on all surfaces. Is it on all the machined surfaces or primarily on one? What you might have is a galvanic cell between the Al part and the freshly machined surface..
Alternatively...
Do you have any odor with the coolant? If so you might have a problem with sulfide reducing bacteria. As part of their biological processes they execrate weak sulfur containing acids -- these acids create the color described on aluminum. If you decide this is the issue you will need to DCR...
They are normally looking from a specific SFPM at the edge of the bowl and as many different operations are done in a mixer it would be unusually to only have 1 speed available -- suggest that you either measure the RPM of the one you are converting or check the catalogue of similar machines --...
The original grinders of this type were call Hanchetts and then Madison Hanchetts.
I don't know if they are still in business but Snow in the UK used to make a good one -- on a practical basis yo might want to buy a used one and have it rebuilt to your specs.
If what you are seeing is fatigue failure at the point of initiation you need to check a few other things as well:
1- how much stock are you taking off -- in other words are all the parts the same size at the point you are cutting both now and in the past
2- are the good broaches ground the same...
