Purchase considerations for tomato box forming machines

6 Pages·1993·0.38 MB·English

by  Goulston, Charles L

Historic, Archive Document
Do not assume content reflects current
scientific knowledge, policies, or practices.

aTS900
.G68
1993 United States Department of Agriculture
Distribution Bulletin
Purchase Considerations for
Tomato Box Forming Machines
By Charles L. Goulstori'
Introduction A Comparison of the Tomato Boxes
Tomato packers use millions ofboxes annually for ship- From aquick glance at the two boxes, they appearthe
ping bulk-packed, mature green and partially ripened same. Theiroutside dimensions, with the lid in place, are
tomatoes. A typical box, including the lid, costs between 60 12 inches by 16 inchesby 9 1/2 inches high; they are 100
and 80 cents. As aresult, packers have acontinuing percent modularto a standard48- by 40-inch pallet. They
incentive to reduce the costofeach box. use the same lid and stack interchangeably on apallet. The
stacking pattern is4-3-3, allowing 10boxes to a layer, and
Some manufacturers ofpackaging equipment sell a 8 layers perpallet. They hold 25 pounds oftomatoes. The
machine that uses athinnerfiberboard to form abox that comer-postbox has slightly less internal volume than the
performs as well as conventional two-ply industry boxes. conventional box due to space taken up by the corner-posts.
The thinnerbox, called acomer-postbox, was redesigned Since the productbeing packed is round, this difference is
to incorporate a vertical reinforcing post in each comer insignificant.
without changing the overall physical dimensions.
There are many ways ofengineering abox to meetthe
This report provides information to tomato packers who are packer’s requirements. Forexample, abox manufacturer
considering switching to machines that formcomer-post can alterthe specifications ofthefiberboard, such asthe
boxes. numberofplies, weight ofthe liners, and weight ofthe
media. In addition, the manufacturercan change the
A tomato packer who purchased acorner-post box machine dimensions ofside flaps without affecting the overall box
provided much ofthe information used in this report. The dimensions. Each ofthese design changes will affectthe
packerused both the comer-post and theconventional price and strength ofthebox.
machine simultaneously, providing side-by-side compari-
sons ofthe machines and the boxes. The packer’s identity Theconventional box is typically made ofatwo-ply
will remain confidential. The U.S. Department ofAgricul- fiberboard. The corner-post box performs acceptably using
ture is grateful to thisfirm because without itscooperation a single-plyfiberboard. Since the amount ofmaterial used
this report could not have been written. is the biggest factorin the cost ofthe box, the single-ply
box should cost less. This may not always be the case since
the actual price ofthe box is based on all ofits specifica-
tions, thequantity purchased, shipping charges, geographi-
cal location ofthe packerand box supplier, etc. (The
cooperatorreported that he was paying about 8 cents per
box less forthe comer-postbox than forthe conventional
' Industrial Engineer,U.S. DepartmentofAgriculture,AgriculturalMarketingService,TransportationandMarketingDivision,
DistributionServices Branch. Formoreinformationortoobtainadditionalcopiesofthisreport,contactUSDA-AMS-TMD-DSB,
P.O. Box96456, Washington,D.C. 20090-6456.
November 1993
3
box.) Once all box specifications have been determined, the plant’s electrical wiring or airsupply systems to accommo-
packer should get price quotes on both types ofboxes from date a new machine. In addition, new conveyors may have
several manufacturers. to be purchased or old ones rearranged so the formed boxes
will flow smoothly from the machine to the packing line.
The corner-post box weighs about 4 ounces less than the Costs for such changes are not included in this report.
conventional box. A pallet stacked with 80corner-post
boxes weighs about 20 pounds less than a similarpallet An important factor in comparing the two machines is the
loaded with conventional boxes. The weight difference for rate ofoutput offormed boxes. Based on discussions with
a truckload of20 pallets is 400 pounds. several users ofboth machines, 38 boxes per minuteforthe
corner-post machine and 45 boxes per minute forthe
The tlat, unformed boxes measure about the same: 30 conventional machine were determined to be realistic
inches by 34 inches. In terms ofstorage space, the conven- operating speeds. Both machinescan run faster, but cost
tional boxes stacked 43 perfoot while the corner-post calculations will be based on 38 and45 boxes per minute,
boxes stacked 65 per foot. These dimensions apply only to respectively. Over extended periods oftime, actual outputs
the two boxes studied, but are probably typical ofsimilar would be somewhat less dueto occasional stoppages
boxes used by other packers. caused by the need to cleara defective box, lubricate
machine surfaces, or remove some stray paper scraps or
The cooperator reported that he used about a pound ofglue, glue.
at a cost ofabout $1.15 per pound, to form 1 15 convention-
al boxes. The corner-post box requires slightly more glue. The size ofa machine may be critical to some packers.
Afterquestioning several other users ofboth types of The corner-post machine measures about 5 feet deep by 1
machines, it was concluded that a reasonable cost ofglue is feet long by 7 1/2 feet high. The conventional machine
1.1 cents perconventional box and 1.3 cents percorner- measures about 5 1/2 feet deep by 5 feet long by 8 feet
post box. high. The corner-post machine occupies more than twice as
much floor space. In addition to being larger, the weightof
Box strength was tested on a ,000-mile shipment. Test the corner-post machine is significantly greater. Size and
1
pallets ofeach box were positioned at the rearofa48-foot weight are important to packers, particularly those who use
by 102-inch space-savertrailer with conventional leaf more than one machine, and those who are accustomed to
springs for shipment to a wholesaler. To prevent shifting of moving machines from one packing shed to another. The
the boxes, which were filled with mature green tomatoes, weight ofa machine is a majorconsideration in older
small amounts ofglue were applied to the top surfaces of packing sheds with wood floors.
their lids. The interior temperature was maintained at about
60 °F. for the 2-day trip. A few boxes nearthe bottom of Performance and reliability are also important factors to
each ofthe test pallets suffered minor collapse. There were consider. Both machines performed well with a few minor
very few damaged tomatoes on eithertest pallet. The problems usually caused by defects in the flat, unformed
difference between those two test pallets was negligible. boxes. In the few instances when the conventional machine
jammed, it generally took less time to clearthejam than
Anothertest was conducted on both types ofboxes using a with the corner-post machine. The conventional machine
compression tester. The boxes tested were obtained from a has a long record ofuse in the tomato industry. Many of
wholesaler and had already been used for one shipment of these machines, in slightly different versions, have been
tomatoes that had been in storage for afew days. There was used for more than 20 years. On the other hand, not much
little difference in performance between the two types of is known about the long-term durability ofthe corner-post
boxes. machine. To facilitate cost calculations, a useful life of20
years is used forboth machines.
A Comparison of the
Box-Forming Machines The corner-post machine is more technically sophisticated
than the conventional machine and design ofthe box
The conventional machine, including delivery and afew requires more critical glue placement. Therefore, proper
accessories such as vacuum feed, costs about $32,000. The adjustment and maintenance ofthe corner-post machine are
corner-post machine, including delivery, costs about more critical and complex. Consquently, the machine
operators and support personnel have to be more highly
$63,000. Similar machines are available from other
manufacturers. Othercosts may include changes to a skilled.
According to the powerconsumption data provided by the annual outputs foreach machine. The lastcolumn oftable
machine manufacturers, conventional machines draw about B lists the annual ownership and operating costs perbox at
13 amps at 220 volts while the comer-post machines draw the assumed annual outputs per machine.
30 amps at 220 volts.
Maintenance and repaircosts are related to thecosts ofthe
Time studies were conducted ofthe laborrequired to machines, as well as to the numberofboxes formed on a
operate and support both machines (maintenance exclud- given machine. In the absence ofactual maintenance and
ed). The largest laborutilization was for loading flat, repaircosts, the average annual cost wascomputed at 2
unformed boxes into the machines. There was more percent ofeach machine’s replacement cost per million
variation between different operators than between ma- boxes formed on the machine. (The repaircosts shown in
chines. Also observed were the handling ofincoming table A represent an average ofthe annual costs incurred
pallets offlat, unformed boxes and the daily cleaning ofthe overthe life ofthe machine. In reality, maintenance and
machines. There was no significant difference between the repaircosts would increase during the life ofthe machine.)
two machines as faras operating them, keeping them Powerconsumption figures are based on calculations using
supplied with flat, unformed boxes, and cleaning them. data supplied by the manufacturers and an assumed unit
Although labor is a legitimate cost, it was not included in electricity cost of6 cents perkilowatt-hour. Footnotes in
the cost tables A and B. each table provide additional explanations.
Ownership and Operating Costs Since the number ofboxes formed annually on a machine
of the Machines will vary by packer, the packer should first determine how
many machines will be needed, and the estimated annual
Following is a discussion ofthe annual ownership and output per machine. These costs are based on the annual
operating costs, averaged overa 20-yearperiod, foreach output per machine and do not apply to the combined
machine. Certain costs are fixed. That is, they will not vary output oftwo or more machines. Iftwo or more machines
with the numberofboxes formed. Othercosts are variable are required, thecosts must be determined separately for
and depend largely on the numberofboxesformed. each machine. (The costs shown can beeasily recalculated
by substituting different data orassumptions, and recon-
Table A lists the components ofthe annual ownership and structing tables A and B.)With this information, the packer
operating costs forboth machines, separating fixed costs can determine the savings needed to be realized percorner-
from variable costs. Table B is aconsolidation and exten- postbox tojustify buying the more expensive machine.
sion ofthecosts in table A based on several assumed
A
Table
Development of Annual Ownership and Operating Costs
FixedCosts Variable Costs
Type of Replacement Estimated Annual Insurance
Machine Cost Life Depreciation' Interest^ andTaxes^ TotaF Power^ Repairs" TotaF
($) (years) ($) ($) ($) ($) ($/thou) ($/thou) ($/thou)
Conventional 32,000 20 1,600 1,920 640 4,160 0.10 0.64 0.74
Corner-post 63,000 20 3,150 3,780 1,260 8,190 0.27 1.26 1.53
Footnotes:
'Basedon20yearlife,straight-linedepreciation,zerosalvagevalue,
-Basedon 12%ofundepreciatedbalanceor6%ofreplacementcost.
^Basedon2%ofreplacementcost.
Total ofdepreciation,interest,insuranceandtaxes,
^ Basedoncalculationsandmanufacturer-supplieddata.
"Basedon2%ofreplacementcostpermillionboxesformed.
’Totalofpowerandrepairs.
Table B 1022440431
Annual Machine Ownership and Operating Costs (per Box)
Annual Output Total Fixed Total Variable Total Total Cost
per Machine Machine Costs' Costs- Costs-’ per Box^
(# ofboxes) ($) ($) ($) (cents)
250,000 Conventional 4,160 185 4,334 1.7
Corner-post 8,190 383 8,573 3.4
500,000 Conventional 4,160 370 4,530 0.9
Corner-post 8,190 765 8,955 1.8
750,000 Conventional 4,160 555 4,715 0.6
Corner-post 8,190 1,148 9,338 1.2
,000,000 Conventional 4,160 740 4,900 0.5
1
Corner-post 8,190 1,530 9,720 1.0
,250,000 Conventional 4,160 925 5,085 0.4
1
Corner-post 8,190 1,912 10,102 0.8
,500,000 Conventional 4,160 1,110 5,270 0.4
1
Corner-post 8,190 2,295 10,485 0.7
Foolnotes:
'Total FixedCosts fromTable A. ’SumofTotal FixedCostsandTotal VariableCosts.
Total VariableCosts fromTable A times Annual OutputperMachine. 'Total Costdividedby Annual OutputperMachine.
Summary requirements, the need for more highly skilled laborto
operate and maintain the corner-post machine, the relative
Before committing to any major purchase ofequipment, immobility ofthe corner-post machine, and the uncertainty
packers should explore alternative ways ofreducing box ofits long-term reliability.
costs. There are many factors to consider when deciding
whetherto purchase acorner-post machine. Most important A packer who operates more than one box forming
is the customers’ requirements. An obvious factor is how machine, with an annual output of500,000 boxes per
much money can be saved in the purchase ofcorner-post machine, has the potential to save tens ofthousands of
boxes versus other boxes. Tables A and B show that the dollars annually provided that management can save
total annual ownership and operating cost per box forthe enough on their box purchases toJustify the additional
corner-post machine is about twice that ofthe conventional machine costs. At that volume, the difference in ownership
machine. Also, the cost ofglue for the corner-post box is a and operating costs between the two machines is about 1
fraction ofa cent more than that ofthe conventional box. cent per box. Afteradding anotherfraction ofacent forthe
Anotherconsideration is that the slower speed ofthe increased cost ofglue, the savings in the purchase price ofa
corner-post machine may necessitate that some packers box does not have to be much tojustify the purchase ofthe
purchase an additional machine to keep up with the more expensive corner-post box machine. The packer
requirements ofthe packing line(s). This may not be should look at several manufacturers’ equipment before
relevant unless a plant is operating its present machines at deciding on a particular machine.
or near capacity. Other factors to keep in mind are space
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