$0.10 a pound cheaper... $.50 less a gallon... 15% savings on nozzles and hoses... procurement is working just like it should be... but turns out 10,000 more pounds, 400 more gallons, and 25 more nozzles were used year to date. Could it be an increase in business? sure. Could it be shoddy quality and cheaper materials... probably.
Vibratory media, blast abrasives, process compounds, spare parts, etc, are quickly devolving into commodities rather than weighted as critical components of a manufacturing process. For basic low demand deburring and blasting processes, commodity quality is generally fine, but when acceptability hinges upon high quality production from the finishing department, companies are quietly taking a huge hit.
If a 5/16 nozzle at 70 psi, wears one-sixteenth of an inch (1/16) (.0625) it will consume around 50 more CFM (12hp) from your compressor, and cycle through roughly 2.5 cubic feet more abrasive per hour. If it wears an eighth of an inch (1/8) (.125) roughly double those figures.
Scale that up to higher production scenarios, amounting to 3 nozzles... 6 nozzles... 20 nozzles... you can immediately see what is happening. Those cheaper nozzles wear in one month rather than six and depending on when the PM schedule (if there is one) tells the operators to change nozzles, you paid for 3000 more hours of compressed air. Meanwhile, that cheaper blast abrasive pulverized to dust in 3 passes instead of 8, but because it's cheaper it the net expense for consumables goes unnoticed. So it Turns out the anodizer has been charging you more because your finish quality is becoming more inconsistent. It is now taking them twice the time to clean and etch before they can finally finish your parts. (which still won't always end up passing your final QC because of finish inconsistencies)
Procurement saved you $0.10 / lbs on vibratory media this order, and as directed, it's an "or similar" media this time around. It's still 1/4 x 9/16... and it's still a grey cylinder so it's thrown in the machine. At the quarterly meeting, Operations reports to the plant manager that they have been picking "stones" out of hundreds of parts by hand for 3 weeks and now parts are being run through the washer too because now they are dirty after vibe. Turns out the media attrition rate is 30% faster, while creating a more dull finish, and leaving media residue in the blind holes... or was it the less expensive vibratory compound they switched to because it saved money up front?
Of course, there are plenty of companies who manage their finishing process with care and are very good about PM and auditing however, historically, not much emphasis is placed on the "finishing" process" while other "more critical" processes get absolutely scrutinized. Speeds and feeds, coating thickness, MPI, corrosion testing... all things that are QC staples... but for some reason prints still call out "bead blast all over" or "tumble for 30 min".
When an entire process's costs are buried in labor and overhead, it is very hard to get a clear picture of what is truly taking place. On paper your "finishing supplies" costs are going down while rejections, labor, overtime, are all slowly increasing disguised as the cost of doing business. Moving to EDI platforms and outsourcing procurement can save you cash upfront, but the decision to move to a less expensive abrasive or process compound should not be left up to purchasing, just because the perception is "it's a consumable".