Warning: This post contains metalworking content - Deburring "Finished" Parts

I make a lot of parts that are generally a rectangular solid. Typically
they have a lot of details machined into one surface making it a mold.
About the most efficient way to finish and deburr that surface is either
to go over it gently with a very fine grit sanding block, or to make a
minimal (or zero) surfacing pass to cut off or fold over the burrs.
Both work pretty well.
Surfacing depending on the part and the machine the part is on can take
upto a few minutes.
Sanding runs the risk of some minor edge erosion of the cavities and
dulling the flat machined face, but is very fast. Usually far less than
a minute. It does require hands on time though.
I prefer the look of a dull sanded surface, and it flattens slightly any
irregularity from tool marks, but some customers judge that as a
negative. They like that bright shiny look even if tool marks are
visible. Polishing is not an option in most cases due to both time, and
possible additional edge erosion.
I've gone to a surfaced finish rather than a sanded one, because its
easier than explaining to people the difference and I don't have to do
more than swap the tool. While it is often slower (on that primary face)
than sanding I do not have to stand there sanding it. The part
effectively gets surfaced twice. Once at the beginning at normal speed,
feed, DOC, WOC, to remove enough material to get a good reasonably flat
face, and a second time very fast with wide WOC and almost zero DOC to
remove burrs from features.
You can pick through that and look for something to bash if you like,
but I've spent a lot of time and have a fair amount of experience that
lead me to that process.
At this point I have a part that is technically functional, but it still
has upto 10 primary edges with what can be much more serious burrs
depending conditions. Four of those might be able to be debured on
machine with a chamfer tool, but as you may be aware unless the tool is
brand new measuring its tool height in a tool holder can be tricky. It
also requires that each piece of stock be precisely pre-sized in both X
and Y before being loaded in the machine. That adds another step that
is not necessary for the part to be functional. Typically unless the
mold is being used in an automated machine and needs to have parallel
faces I do not even machine 3 of the 6 faces on the part. Time saved is
time saved. Two of the faces often only need to be machined to remove
the obnoxiously ugly saw cut end and allow for re-indexing if multiple
setups are required or minor recuts need to be done.
Anyway, I have upto 10 edges that still need to be deburred. Even if I
did chamfer that top I would still have 6. If both ends of the part
happen to hang out of the vise or fixture it might be possible to
chamfer 4 more of those with an end mill. If those ends hang out an
under cut tool, back chamfer tool or even a single point thread milling
tool could cut a chamfer on the two remaining edges.
AGAIN: You can pick through that and look for something to bash if you
like, but I've spent a lot of time thinking about all of these things
and have my reasons for why that is not always efficient. In fact its
rarely efficient. I routinely cut parts that are smaller than the vise
width when I use a vise, but more often I am using fixture plates to
maximize the part density on the machine. This saves crazy amounts of
time to produce parts. Sure I could make more complex fixture plates
with clearances for all of those things, but then part indexing time and
part density starts to suffer. If I can run 2 parts instead of one I
halved the tool changes. If I can run 4 parts instead of 1 I have 1/4
of the number of tool changes. That is a crazy amount of time savings
on a small production run. No I do not have big fancy high end
production machines with automatic tool changers and chip to chip times
measured in seconds, if I did machine time efficiency might be more
important and seconds be more important as well in order to pay for the
machines.
Anyway, all of that has two purposes. The primary one is to provide
background and explanation for my quandary about removing the burrs from
those last ten edges when all else is done. The other absolutely not
intended and not wanted purpose was to give nitpickers and
judgmentalists something to peruse looking for a minor part to attack so
they can feel better about themselves.
What I do now is one of three things depending on the part and how I
feel at the moment. I'll knock the burrs off those ten edges with a
sanding block or with a file. I'll walk back and hit the edges on the
little 1x30 belt grinder. I'll worry the edges away with a stainless
steel wire bush on the bench grinder. File tends to require coarse and
then fine faces to be used at two angles. Sanding block tends to leave
the nicest most consistent edge. Belt grinder is by far the fastest.
Wire wheel is the slowest and often does not remove the burr. It just
rounds it over unless I go back and forth from both sides of the edge.
A harder wire wheel might do a better job, but it also leaves open the
potential for more damage.
Some of the things I am exploring are:
A carbide tool chamfering machine that basically runs like a router
table. I think dialing it in to remove just enough material to debur
(yes I know it may leave its own much smaller burr) on most of the sides
of the nearly finished part it will be tricky, but once adjusted will
work for many parts. Probably longer than the life of a belt on the
belt grinder. Then it can probably be adjusted to use another section
of the cutter edge. I think it would work adequately on all of the
longer edges, but on many parts it would still leave 4 short edges that
may not be safe to debur on this machine. Maybe a moving t-slot
T-tool/gage and a clamp could make this safer.
The other is a better quality belt grinder and surface conditioning
belts. The thing is I can't run surface conditioning belts on my
current belt grinder. It doesn't have the power. I have never used a
surface conditioning belt so I don't know if its worth the time to build
or cost to buy a machine that will run them.
I could build either machine in a day. My ego says a few hours, but my
experience tells me a long day. Maybe two. Or I could buy something
that may or may not address the the potential issues I already see with
either.
The chamfering machine might be marginally better if for every part that
really is just a rectangular solid, but I do make a fair number that
have boss features along one end for making a hinge. There is no way I
know of to use a chamfering machine to clean up the burrs on those edges.
Time is the most valuable and most finite commodity in my shop. If I
spend some time today working on this I want to make sure it will save
me a little time everyday hereafter.
For many who would sincerely try to help I apologize for my writing
style. I hope to prevent or atleast reduce those comments that would
force me to go back and defend or justify processes I have already
decided upon based on experience and what I believe to be good reason.
If you are one of those who would choose anyway to attack or pick at one
of those things instead of focusing on the core quandary please take the
time to explain in detail and defend your choice as well as including a
superior solution along with your explanation and defense of it as
opposed to other solutions.
Reply to
Bob La Londe
Loading thread data ...
Within seconds of hitting send I realized there were a few obvious things one might question. "How can you machine the saw cut ends off if they do not stick out of the vise?" is one such. I have a solution for that which does not leave fully open the bottom and corners for alternative chamfering and burr removal. One part (or class of part) I make routinely has blanks roughed out nine at a time on one machine, and finished four at a time on either of two other machines. All are done in fixture plates to maximize part density. Time saved is dramatic over using a single piece in a vise or even one each in two vises.
Reply to
Bob La Londe
... Anyway, I have up to 10 edges that still need to be deburred. ... -------------------- The air powered 2" disk and 1/2" belt sanders I bought for auto body repair have proven quite useful for general deburring and rust removal, mainly because of their small size and maneuverability. Today I used the disk sander to cut down the narrow rust rings on my disk brake rotors without scratching the braking surface.
Reply to
Jim Wilkins
What type of pad are you using on the little 2" discs? I actually have a variety of those and considered making a motor arbor to mount one of the mandrels for deburring non linear and harder to reach edges.
Of course I have a cheap right angel die grinder with a 2" disc mandrel on it as well.
Reply to
Bob La Londe
...
What type of pad are you using on the little 2" discs? I actually have a variety of those and considered making a motor arbor to mount one of the mandrels for deburring non linear and harder to reach edges.
Of course I have a cheap right angel die grinder with a 2" disc mandrel on it as well.
---------------------- The disks are Harbor Freight, the belts from Amazon, for an Eversharp which takes the same 1/2" x 12" size as my air tool.
At HF I bought a sample of everything in 2" and 3" that looked like it might be useful, both twist-on and hook/loop, including larger pads to cut down. Hardly any of it fit the RA sander until I made a 1/4-20 arbor from threaded rod. They came with arbors meant for a drill chuck, fortunately also 1/4-20 so I didn't have to complete the metric threading conversion on my old US lathe (I did anyway). My die for cutting 2" pads from 6" ones is a short piece of 2" pipe with a sharp edge. Having the paper disk larger than the backing pad helps feather edges and sand internal rounded corners.
I assembled the backing disks directly against the spindle so they rotate with it instead of oscillating, as they would with a small washer or nut on the arbor to disconnect the inner oscillating section from the rotating spindle. One 2" fiber matte pad quickly stripped paint and rust from four 3" x 8' salvaged steel channels and then nicely smoothed and shined the leaking, corroded tire bead seating surfaces on my sawmill's ex-motorcycle alloy drive wheel.
I bought the RA air sander after having a lot of trouble smoothing the MIG welds on a saddle-curved fender repair with hand tools. So far the rust hasn't reappeared and I haven't needed the sander for the reason I bought it, which is just fine with me, call it cheap insurance. Body shop estimates on the repairs I did exceeded the value of the vehicle.
I no longer have to work to customer-acceptance finish quality but I think the job these tools can do might pass. The Eversharp assortment included 1200 grit belts. jsw
Reply to
Jim Wilkins
My deburring consists of belt sander, conditioning wheel on 6" bench grinder or a vibratory tub.
Outside edges get the belt sander if it's quick and dirty part, conditioning wheel for finer parts and the tub for internal burrs (at least on parts with large internal features).
I have "sand" blasted some parts to deburr them.
Reply to
randy333
The John Doe troll stated the following in message-id :
And the John Doe troll stated the following in message-id :
And yet, the clueless John Doe troll has itself posted yet another incorrectly formatted USENET posting on Fri, 12 Nov 2021 08:11:47 -0000 (UTC) in message-id .
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Reply to
Edward Hernandez
The nym-shifting stalker Corvid/Edward/others is upset because it will never again troll USENET without its nyms being exposed.
Corvid perpetually proves why it must nym-shift. Its mission, as always... annoy everybody.
see also... Cörvid ? Cows are Nice ? Banders Covid-19 Corvid Corvid Cows Are Nice Cows are nice Cows are Nice dogs Edward H. Edward Hernandez Great Pumpkin Jose Curvo Local Favorite Peter Weiner Sea Standard Poodle triangles and others...
Reply to
John Doe
The John Doe troll stated the following in message-id :
And the John Doe troll stated the following in message-id :
And yet, the clueless John Doe troll has itself posted yet another incorrectly formatted USENET posting on Fri, 12 Nov 2021 15:03:25 -0000 (UTC) in message-id .
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Reply to
Edward Hernandez

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