Boosting operating efficiency, servicing ease and operator comfort, the new Caterpillar 302.7 CR, 303 CR and 303.5 CR hydraulic mini excavators were recently unveiled. Built on the Next Generation platform that offers a consistent operator experience through the 1.5- to 10-ton range, each new model features exclusive stick steer, cruise control, operator adjustable settings, and tilt-up canopy or cab as standard.
The latest models replace the 20-year old 302.7 D, the 15-year-old 303 E and the 10-year-old design of the 303.5 E2.
“It's time to go away and be replaced by three brand new models, with a lot of commonality, a lot of similarities but also a lot of big differences,” says Greg Worley, Caterpillar market professional. He says expanded use of common parts throughout the line plus their damage-resistant exterior construction help to reduce parts inventory investment and lower repair costs. Also, daily maintenance checks are quickly made from ground level through side doors, while the tilt-up cab design offers unmatched access to components for servicing.
“When you're dealing with the machine of this size technicians and mechanics have told us that there's just not a lot of real estate for getting the job done,” says Mark Perkes, product application specialist. Tilt-up cab designs available on the 1- and 2-ton machines are available on these models as well. With the same tools used to lift the Caterpillar skid steer cabs, the excavator cabs can be lifted in less than three minutes. “This is not something you would need to do for daily maintenance,” Perkes says. “That can be done just by walking around the machine and open in those side panels.”
Increased service intervals mean these excavators spend more time on the job and less time in the workshop. Combined, Perkes says these features lower total ownership costs up to 5% compared to previous models.
At the same time, design enhancements for the new 302.7 CR, 303 CR and 303.5 CR deliver up to 10% more performance in travel and trenching. Hydraulic system upgrades improve lifting performance and cycle times, while customizable operator settings improve efficiency. 
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The turbocharged Cat C1.1 Turbo engine powers the 302.7 CR and 303 CR models, while the Cat C1.7 anchors the powertrain for the 303.5 CR. Both engines meet U.S. EPA Tier 4 Final emissions standards and offer 23.6 hp (17.6 kW) net power. Standard auto idle and auto engine shutdown help to conserve fuel usage at the site for more affordable operation.
Flexibility increases performance
Each of these Next Generation mini hydraulic excavators feature a compact radius swing that reduces overhang when working to the side, allowing the machines to optimize performance in confined spaces.
“A big determining factor for these machines is access,” Worley says.
Fixed undercarriage widths for the 302.7 CR, 303 CR and 303.5 CR of 59.1, 61.0 and 70.1 in (1,500, 1550 and 1780 mm) respectively, deliver the right balance of job site accessibility and stability for lifting performance. Worley says an expandable undercarriage option for the 302.7 CR allows the operator to hydraulically retract track width to 53.3 in (1355 mm) for fitting into confined spaces and then expand width to 70.1 in (1780 mm) for superior digging and lifting stability.
Even with increased performance, safety is always first and foremost. “We want to make sure everyone goes home safely every day and one of the things that we do that add safety to a job site is we have an integrated lifting eye on the bucket linkage,” Perkes says. With some other machines on the market, customers will wrap a chain around the bucket tooth, which can be unpredictable and potentially unsafe. “With our setup, we have an integrated, certified lifting eye, which is predictable,” he says.
Interchangeable counterweight packages enable customers to tailor machine weight to job requirements, offering the balance between low ground pressure and lifting performance. The “light” counterweight option adds 221 lb (100 kg) to machine weight, while the “extra” adds 551 lb (250 kg).
Worley says all three Next Gen models offer both standard- and long-stick configurations to increase machine versatility. Standard digging depths range from 96.5 to 110.6 in (2450 to 2810 mm), while the long stick configuration allows the machines to reach from 104.3- to 122.4-in (2650- to 3110-mm) depths. The standard dozer blade further increases machine flexibility to handle backfilling and grading tasks. It features ample above- and below-grade travel and has a standard float function for easy clean-up. An angle blade option on the 303.5 CR gives further flexibility in backfilling applications for increased productivity.
Efficient load-sensing hydraulics with variable displacement pump provides oil flow reaching 26 gal/min (100 L/min) while saving fuel. High main-relief pressures, coupled with flow rates, generates the hydraulic capacity for high digging and lifting forces and more efficient use of a range of attachments. Complete with quick-disconnect lines, the standard auxiliary system provides the choice of one-way, two-way or continuous flow.
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Comfortable experience
Worley says the new 302.7 CR, 303 CR and 303.5 CR offer enhanced machine security options, with both a passcode and Bluetooth key start available. Offering an advanced touchscreen option, the large Next Generation display provides intuitive machine function control and easy monitoring of critical operating parameters, such as fuel level, coolant temperature and maintenance records.
A Cat Stick Steer system simplifies machine control, and, at the touch of a button, the operator switches from conventional lever/foot-pedal steering controls to low-effort joystick operation. Two travel ranges with speeds reaching 2.8 mph (4.5 km/h) help to facilitate moving around the jobsite, and standard cruise control minimizes operator interaction when traveling longer distances between work locations.
“With all the customers we’ve talked to, using sticks to cruise control, they've been able to use mini excavators in ways they've never been able to before,” Worley says. “If you don't even want to go that route, you still have the traditional control so we're able to accommodate everybody. We're making sort of average operators, better operators and in doing so, we're not hindering the expert operators out there because they can still use the machine how they want and actually get even more out of the machine and become super operators.” 
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Unique to their respective classes, these new Next Generation excavators offer the choice between canopy or cab enclosure. Worley says the sealed and pressurized cab offers a clean and quiet environment for the operator and can be equipped with heating and/or air conditioning for all-weather climate control. Offering a front window that slides upward to conveniently store overhead, the cab’s large glass areas plus skylight afford all-around visibility.
Layout of the cab has been designed to be similar across models. “Customers told us that a lot of operators will hope multiple models throughout the week, they might be in a 303.5 today and a 310 tomorrow,” Worley says. “Now we’ve made that a common experience across the entire range. If I can operate a 336, I'm pretty sure I can operate this because it looks exactly the same.”
